Overview
Key FeaturesKey Features Learn More
Key Features
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Wide BrimWide Brim
Wider than traditional helmet visors, the front and outward extension protects riders from sun damage and reduces glare. Size may vary by brand or helmet style.
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Dial AdjustabilityDial Adjustability
Featuring an adjustable dial at the back of the helmet, these can either be tightened or loosened to correct minor helmet fitting issues and create the perfect fit.
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Removable LinerRemovable Liner
These helmets have liners that can be removed for easy cleaning or to adjust fit.
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Customizable OptionsCustomizable Options
These helmets allow you to personalize your helmet with front, back, or top inserts in numerous colors and patterns that show off your individual style.
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Round ShapeRound Shape
These helmets are the most comfortable option for riders with a rounder-shaped head. Click here to determine your head shape.
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Oval ShapeOval Shape
Riders with an oval-shaped head will feel most comfortable in these helmets. Click here to determine your head shape.
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Universal ShapeUniversal Shape
These helmets can fit any head shape through changing of liners, dial adjustability, or various shell sizes so you can find the right fit for your head's size and shape.
Safety MeasuresSafety Measures Learn More
Safety Measures
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ASTM/SEI CertifiedASTM/SEI Certified
The American Society for Testing and Materials (ASTM) writes widely known safety standards, then an independent testing laboratory called the Safety Equipment Institute (SEI) ensures that manufacturers design helmets that are up to par. The ASTM/SEI testing standard requires impact and retention tests, as well as a visor test to make sure that the visor breaks away or flexes without injuring the face.
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European CertifiedEuropean Certified
European standards are put together by a committee comprised of representatives from countries in the EU. In addition to impact, retention, and visor tests, these safety standards demand that helmets withstand penetration and crushing. The inclusion of the latter two tests is thought to produce safer helmets than those only certified to ASTM standards by SEI.
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SNELL CertifiedSNELL Certified
The Snell Foundation uses what is considered the most demanding testing procedure for riding helmets. Their tests include all aspects of the other certifications but with more stringent standards. Snell drops the helmets from a greater height during the impact test onto a variety of differently-shaped anvils, has the highest crush resistance rating, and ensures the helmet offers sufficient head coverage without sacrificing the rider's field of vision.
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MIPSMIPS
MIPS, or Multi-Directional Impact Protection System, is an additional layer embedded in some helmets to reduce strain on the brain upon a fall. When the helmet makes contact with a surface, the low-friction MIPS layer allows the head to move 10 to 15 mm in all directions to dissipate impact on the brain.
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ERT FoamERT Foam
ERT, or Energy Reduction Technology, consists of soft polymer pads incorporated into the helmet design that mitigates rotational and linear impact. With the motto "Softer is Safer", ERT works immediately and is most effective with lower-impact falls.
Enter the show ring with sophisticated style and undeniable comfort with the One K Defender Riding Helmet. A sleek injection-molded outer shell with discreet stainless steel ventilation panels boasts a professional finish to appeal to even the most discerning of fashion-forward equestrians. Modern technology ensures maximum safety while unique user-friendly features provide optimal comfort, durability, and ease of use.
With a washable, quick-dry, anti-microbial lining system, the One K Defender stands true to its name to fight moisture build-up and prevent odor and discomfort. A unique padded harness with a soft synthetic suede lining features Velcro adjustment options for a truly customized fit while the Fastex® chin buckle allows one-handed ease of use!
Details
- Polycarbonate/Advanced ABS Composite Outer Shell
- Washable, Quick-Dry Lining with Anti-Microbial Protection
- Sleek, Stainless Steel Mesh Ventilation Channels
- Comfort Padded Harness with Soft Synthetic Suede Lining
- Customizable Velcro-Adjustment Chin Strap with Fastex® Buckle
- Painted Matte Finish for a Sleek & Professional Appeal
- ASTM F1163-15/SEI Certified
Additional Information
One K offers a 3-year replacement policy if your helmet is in an accident. See information about this policy here.
Sizing
Please Note: Check the sizing chart and measure, as these helmets may run small.
| Size | Head Circumference | Cap Size |
|---|---|---|
| XS | 51 - 52 cm | 6 3/8 - 6 1/2 |
| SM | 53 - 54 cm | 6 5/8 - 6 3/4 |
| MD | 55 - 56 cm | 6 7/8 - 7 |
| LG | 57 - 58 cm | 7 1/8 - 7 1/4 |
| XL | 59 - 60 cm | 7 3/8 - 7 1/2 |
| XXL | 61 - 62cm | 7 5/8 - 7 3/4 |
See how a helmet should correctly fit with Kim Gentry in this helpful sizing video.
Previous Feedback
Comments: THE BEST HELMET EVER! I love the fit on these helmets - it's perfect. They are comfortable and fit snugly. Will be my go to for now on and you can't beat Riding Warehouse's shipping!
From: Alexandra - San Jose, California, USA
Comments: I've had many helmets over the years, and the One K has by far been my favorite. The sleek shell of the defender not only looks good, but is comfortable, and the removable inserts make it a breeze to wash or to change the fit of the helmet for when I have my hair in a ponytail. The cherry on top is that it is budget friendly!
From: Cenn - St. Charles, Illinois, USA
Comments: Beautiful, elegant style and wonderful fit. I have a very uneven shaped head and subsequently tried on numerous helmets to no avail. Fortunately this helmet fits like a glove. I love the comfort of the foam in the liner and the ability to remove, machine wash, and replace the liner. I also love that I can simply move up to a larger size liner when I put my hair in a net/grow my hair out. RW customer service was excellent and shipping across the country was so fast. *Almost* want to buy another one in the rose gold!
From: Janice- Texas, USA
Comments: I put this helmet on, and I swear I heard angels singing. I was a bit worried about S/M/L sizing, as I typically wear either a 6 3/4 or a 6 7/8, but I ordered a medium long oval and hoped for the best. It is PERFECTION. I can turn my head upside down without fastening the harness and the helmet does not fall off, yet I just walked around my house for 2 hours and there's no hint of a pressure spot on my forehead or a headache, which is my usual problem trying to make round-ish helmets fit my oval head. I don't love the angle of the chin harness - it seems to come too far forward, almost jabbing into my chin, but it seems like that will stretch and soften with time. Thanks to RW's generous return policy, I tried and returned 2 sizes of the IRH Elite (6 7/8 was too big, but 6 3/4 seemed perched) and the CO Pro II. Glad the 4th (eek) time was finally the charm. Thank you for carrying the long oval shape, and for not cutting me off as a customer after so many returns ;)
From: Jennifer - Pittsburg, Pennsylvania, USA
Comments: This helmet gets a lot of compliments. I just took a fall wearing this helmet and while I'm pretty well bruised and the helmet needs to be replaced I can say the my head was well protected.
From: Yvonne - Rochester, New York, USA
Comments: Fits great and feels very secure. I keep a spare liner to switch out every few rides. It stays comfortable for long rides and never makes my head hurt. I don't notice a huge difference with keeping my head cooler, though.
From: Abigail - Petaluma, California, USA
Comments: Ah-mazing helmet! Worth every penny. Fits snugly enough - it feels secure but doesn't smother you. Looks really good too!
From: Rebekah - Turlock, California, USA
Comments: Super profile with a beautiful color. The first helmet I ordered had issues with the liner, but Riding Warehouse promptly exchanged it for me. Couldn't be happier with this purchase!
From: Dani- Milwaukee, Wisconsin, USA
Comments: Best fitting helmet and at a reasonable price! Great lightweight helmet that actually fits my tiny head. Vented and comfortable even with our hot, humid summers. The lining can be taken out and washed. Love this helmet.
From: Shelton- Charleston, South Carolina, USA
Comments: It took me a long time to find a helmet that I liked the look of, and I am so glad I found the One K... I LOVE it...it is super easy to keep clean too!!
From: Stephani - Anchorage, AK, U.S.A.
Comments: Love the profile and is the first helmet that actually fits my small head! Service was excellent and arrived as scheduled per tracking! Will definitely shop here again! Thx!
From: Carole - Peach Bottom, PA, U.S.A.