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One K Defender Matte Helmet

One K - Item #21807
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As riders and online shoppers, we know it can be tough to buy a new bridle or pair of boots without trying them on. That's why we moved the fitting room to your living room (or barn)! From breeches to blankets, if you or your horse can try it on, you can return it, free! Just request a return with a FREE SmartPak return label from your Order History within 60 days of the purchase date. And of course, please make sure the item is in like-new condition with original packaging (we said 'fitting room', not 'war room'!).

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You'll love our AutoShip because it's:
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PLUS! You'll save % on every shipment if you order this product on AutoShip
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Why We Love This

One K™ Defender riding helmets boast the perfect synergy between advanced technology and aesthetically pleasing design. This helmet features a polycarbonate and advanced ABS composite outer shell that’s tough but lightweight with a modern matte finish. It’s offered in both an oval shape and a round shape so that you can find the perfect fit for your head. You’ll love that the liner is moisture wicking, quick drying, anti-microbial, and washable to keep you cool, dry, and comfortable. Plus, the harness is padded for comfort and lined with easy-to-care-for synthetic suede to keep you as comfortable as you are stylish. It even has a Fastex buckle that makes taking it quick and easy to take on and off. Additionally, you’ll have plenty of ventilation with two side, two front, one back, and two center stripe vents for a total of seven vents. Last but not least, this helmet is ASTM/SEI F1163-15 certified, so you can have peace of mind that your head is in good heads. With enough features to appeal to those seeking everything a horseback riding helmet could offer, wrapped in a stylish package that traditionalists can appreciate, One K™ has the best of both worlds.

Additional One K Helmet Liners also available!

  • Polycarbonate and advanced ABS composite outer shell is tough but lightweight
  • Offered in oval and round shapes for a great fit
  • Inner lining is anti-microbial, moisture wicking, quick drying, and washable
  • Comfort padded harness with synthetic suede lining and Fastex buckle is comfortable, easy to use, and stylish
  • ASTM/SEI F1163-15 certified
  • Lots of vents to keep you cool and dry
  • Stylish design looks great in the ring
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The reviews provided on this website represent the experience of the individual posting the review. We do not adopt, edit, or endorse any of the submissions posted within the reviews section. Rather, the reviews are part of an online community of animal owners that desire to share their particular experience with other individuals. These reviews are not a substitute for discussing the health of your animal with a veterinarian.

SmartPak customers are some of the most conscientious animal owners around. We encourage you to share your experience with the products we sell to help fellow customers to make informed choices for their animals. We do not edit these reviews in any way - they are direct customer-to-customer communication. We do monitor reviews for positive and negative feedback, and use this feedback to improve our selection as well as sharing feedback with product manufacturers to help them improve their products. Please note that we recommend consulting your vet with serious health issues.

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    One K Defender Matte Helmet is rated 4.7 out of 5 by 177.
    Rated 5 out of 5 by from Perfect for Round Heads I'm on my second One K, and I love this helmet! I have a round shaped head, and helmet like the Charles Owen often give me headaches on the sides of my head. This helmet fits exceptionally well, and the moment I first put it on it felt secure and like it would provide great protection in a fall. It's light enough with great ventilation for the Texas summers, and I really like that the liners are removable so you can wash them. Turns out I'm on my second one because I did fall off my 4 year old. It was a shame throwing out the first one because it still looked beautiful, but I'm thankful to have had such a well designed helmet on my head!
    Date published: 2019-12-26
    Rated 5 out of 5 by from Comfortable and good looking! This is the second One K Defender helmet I’ve owned. I’ve tried a lot of others because I have a horse-stuff buying sickness (LOL!). This is, by far, the most comfortable and good looking helmet I own. Pay attention to whether you need the round one or the oblong one. I needed oblong and was surprised because I’ve never thought of my head being oblong. After measuring it, it obviously is. I love how it fits!! You can’t go wrong... it looks great in the barn and at the shows!
    Date published: 2019-12-20
    Rated 4 out of 5 by from Great helmet, but chin strap needs work Bought this in a Long Oval, which fits my head perfectly. Very comfortable helmet, and looks great. The harness / chin strap, however, needs to go back to the old design. You can only adjust one side, and even then your adjustments are limited due to the velcro closure. In order to fit around my cheeks and jaw without pinching, I can only close half the velcro. The chin strap is also angled more forward than other helmets, so it sits farther forward on your cheeks and chin. The old One K helmets were not like this. Helmet is great...chin strap is NOT.
    Date published: 2019-12-02
    Rated 5 out of 5 by from Safety first Just bought this helmet for my daughter. I chose this helmet based on the safety specs and overall look
    Date published: 2019-11-15
    Rated 4 out of 5 by from Lightweight, stylish Love the removable liner, great for hot climates. I got this to wear on the flat and arena jump schooling. I will wear my Charles Owen for cross country as this seems too light for xc. Love the Navy! Fit seems great, love the chinstrap design.
    Date published: 2019-07-23
    Rated 5 out of 5 by from Great ventilation and comfort! I was looking for a new helmet because my old one didn't have enough vents and my head got so overheated and I became dizzy while riding. I tried many different helmet brands and this helmet fit me the best. I wanted something that was nice looking for the hunter shows I am in, but I didn't want to spend too much money because I am still growing. This helmet is a great price and is an awesome helmet.
    Date published: 2019-07-16
    Rated 3 out of 5 by from Great helmet, but poorly angled chin strap I loved the oval helmet, but the chin strap didn't work for me. It is angled too forward for my face. I wish the strap had more webbing on it instead of the stiffer plastic. The helmet fit well and I liked the venting. The small fit me, while the medium was too big and my measurement (6 7/8) was the low end of the medium. I returned the helmet due to the chin strap issue.
    Date published: 2019-07-06
    Rated 5 out of 5 by from I ordered the Large (Long Oval) since my head measures to 7 1/8 with my hair down and 7 1/4 with it up for shows. I had previously been using a 7 1/4 Charles Owen JR8, but I school in a M/L Ovation helmet with an adjustable dial. This helmet will soon be too big with my hair down, it feels like it will start wiggling once the padding compresses due to wear. With my hair up it is perfect and comfortable enough even in the summer heat - certainly better than my Charles Owen! I bought it as a show helmet so it's all good! Just know it measures towards the larger size, not the smaller one in the range given. This will be especially noticeable when the padding compresses.
    Date published: 2019-07-03
    Rated 5 out of 5 by from Super Comfortable So happy with this purchase! Very comfortable and vented well.
    Date published: 2019-07-03
    Rated 5 out of 5 by from Great fit, great quality I bought this helmet a couple weeks ago, so I don't have a ton of experience with it yet, but my head measured exactly at the borderline between small and medium and I got a small to be safe as that is what my old helmet was. The small fits great and the dial used to adjust it is a great addition for people like me who didn't know if the small would be too small. Fits great, feels sturdy and I show jumpers and this is totally suitable for local jumper shows. I wouldn't suggest it for rated just because of the dark grey color (not black)
    Date published: 2019-06-02
    Rated 5 out of 5 by from Perfect for hard to fit daughter This is the ONLY brand of helmet that fits my 10 year old with a round head. We have tried all the others and this fits like a glove. Lightweight, cool in hot temps and low profile. We just purchased her a second in navy and it is gorgeous!!
    Date published: 2019-05-22
    Rated 5 out of 5 by from Excellent fit I transitioned from a Samshield to the One Ks after getting sick of spending $400 every time I would hit my head badlyl enough to replace my helmet. The finish is very clean, there are more vents, and I'm a 7 so the Medium fits great. I tried the regular (round) fit.
    Date published: 2019-01-24
    Rated 5 out of 5 by from Great fit I bought this helmet for hunter shows and it fits perfectly. I have struggled to find one that fits and looks great and this one has met all my standards
    Date published: 2018-10-22
    Rated 5 out of 5 by from Cool helmet and light Love love this helmet! Super light weight and ventilation is great! I’m in Texas and it is hot! I’ve always worn and love Charles Owens but the price tag and they are hot. I have the oval one k and it fits me fabulously!
    Date published: 2018-10-08
    Rated 5 out of 5 by from Love the helmet For the last several years I bought this helmet (one just for shows, one in Blue and one for every day riding). They have always started off tight (I have a bony growth like a small horn) but use to it. So when the oval one was offered I figured it would not be as tight. Well it ended up being really loose to the point I couldn’t bend over it would slip right off. I still love this helmet but the oval one just didn’t fit like I wanted It to. Though I might try downsizing next time....hmmm
    Date published: 2018-09-27
    Rated 4 out of 5 by from Love it Very comfortable, very nice little looking helmet. I like the fact that the inside liner is removable for washing. This helmet seems like more for my money. The vents keep my head cooler, too. My only complaint is the chin strap sits at a funny angle.
    Date published: 2018-09-16
    Rated 5 out of 5 by from LOVE! I am a long oval FAN! CO helmets gave me a headache. GONE with this shape! The brown is stunning!
    Date published: 2018-09-13
    Rated 5 out of 5 by from Love it I love this helmet, it fits and looks great. I bought the regular round.
    Date published: 2018-09-10
    Rated 5 out of 5 by from Stylish comfortable helmet Been searching for a helmet that fits my oval head and well this not only fits well , but it’s really comfortable and stylish !!
    Date published: 2018-09-10
    Rated 5 out of 5 by from Love this helmet I have a small odd shaped head apparently and this is one of two helmets that just don't look absolutely ridiculous on me.
    Date published: 2018-09-10
    Rated 5 out of 5 by from Great and affordable Helmet I just bought my second One K Defender because I loved it so much. One of the more affordable options in helmets these days but still a great looking one. I love that you can remove and wash the liner as well as buy replacements for the liner if needed or if an extra is wanted.
    Date published: 2018-09-10
    Rated 5 out of 5 by from My favorite helmet I sustained a really bad fall in this helmet in May and the helmet protected me better than I have seen many helmets (including my GPAs). I immediately bought a new one of this same helmet to replace my old one and won't consider any other brand. Bonus that it doesn't make me look like an egg head!
    Date published: 2018-09-10
    Rated 5 out of 5 by from Perfect helmet for me I absolutely love this helmet. It’s beautiful, lightweight, and fits the shape of my head perfectly- like it’s not even there. I’ve had it four months, I ride at least about 3x a week and I can’t find anything bad to say about it so far. I love the removable liner so I can wash the interior and don’t breakout on my forehead. The removable liner is a must for anyone whos head sweats when they ride! I also love the chin strap because it has padded leather on it- looks nice and you don’t even know it’s there. Ive used Charles Owen JR8, Tipperary, international and ovation helmets before- they do not compare.. You get the best bang for your buck too, in my opinion. I don’t think I’ll go with any other helmet. I went with a small and it fits true to measurements for me. I would say my head is more oval than round shape. I it in the bag and don’t bang it around on things/treat it gently when not wearing it and it looks brand new!
    Date published: 2018-09-08
    Rated 5 out of 5 by from Beautiful helmet - cool and great-fitting! I bought the long oval in blue and it's beautiful and so comfortable -- cool in the Texas heat and great-fitting! I'm not have any trouble or discomfort with the chin strap, but this is the most expensive helmet I've ever owned:)
    Date published: 2018-07-19
    Rated 5 out of 5 by from Amazing I bought this a few months ago and recently was flipped over my horses head and landed straight on the top of my head. Thanks to this helmet I do not have a concussion and the plastic shell did not crack.
    Date published: 2018-07-03
    Rated 5 out of 5 by from This replaces a One K that I used for 4 years. Took a pretty hard fall and it did the job we all hope for. My old One K was the suede which I think looked a bit sleeker than the matte but my brain and skull don't really care what it looks like. Thanks Smartpak for including a small and medium liner for the medium helmet. I have very short hair and definitely needed the snugger fit.
    Date published: 2018-06-11
    Rated 5 out of 5 by from I bought this for my 10 year old daughter after a fall and break of her old helmet. I was looking for something safer and that covered the back of her lower head better. They sent two helmet pads with the helmet and a note saying the second pad was a gift if it created the perfect fit. That additional pad made the fit perfect and now she can grow into the helmet so it makes the price just right for me.
    Date published: 2018-06-05
    Rated 5 out of 5 by from Helmet Love the way it fits my head! Keeps my head cool when I ride.
    Date published: 2018-05-14
    Rated 5 out of 5 by from Perfect fit! I can't say enough good things about this helmet. My favorite thing is that it fits perfectly and is so comfortable I don't even feel it!
    Date published: 2018-04-19
    Rated 5 out of 5 by from Great fit! I have a hard time finding helmets that fit me properly. After searching for a new show helmet, I was happy to learn One K offered a round fit helmet. It's perfect!
    Date published: 2018-04-09
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