• Photo of One K Defender Helmet
  • Photo of One K Defender Helmet in Matte Black
  • Photo of One K Defender Helmet in Glossy Black Chrome

One K Defender Helmet

Sorry, currently out of stock

Click here to be notified by email when One K Defender Helmet becomes available.

PRE-ORDER | Please allow 4-6 weeks for delivery. 

Medium Shell comes with a Medium Liner 

Large Shell comes with a Large Liner

To change the fit to a Small | 53-54cm, you need to purchase a Medium Shell and a Small Liner.

To change the fit to an XL | 59-60cm, you need to purchase a Large Shell and an XL Liner. 

Small & XL or spare liners, can be purchased here.

The Defender features: 

  • Polycarbonate and Advanced ABS Composite outer shell
  • Injection molded shell design
  • Washable, replaceable, quick-dry, moisture wicking and anti-microbial liner
  • Stainless steel mesh
  • Comfort padded harness with synthetic suede lining, hook & loop adjustment, and Fastex buckle
  • Seven vents - two side, two front, one back, and two centre stripe vents

One K™ Helmets boast the perfect synergy between advanced technology and aesthetically pleasing design. With enough features to appeal to those seeking everything a helmet could possibly offer, wrapped in a package that traditionalists can appreciate, One K™ has the best of both worlds.  

ASTM F1163 (SEI marked) - approved to current 2019 Australian standards. 


The base shells for the Defender are Medium and Large.

- Use the Medium size helmet shell with a Small liner to change the fit to a Small.

- Use the Large size helmet shell with an XLarge liner to change the fit to an XLarge.

Please note, the Medium Shell is only compatible with Small & Medium Liners and the Large Shell is only compatible with Large & Extra Large Liners.

Spare liners can be purchased here.


Small 53-54CM (6 3/8 – 6 1/2) Large 57-58CM (7 1/8 – 7 1/4)
Medium 55-56CM (6 5/8 – 6 3/4) XLarge 59-60CM (7 3/8 – 7 1/2)