Easily Change the size of your One K Defender Helmet by changing the liner! This provides the ultimate flexibility for growing children, shared helmets, or those who wear their hair differently for schooling and show. Instantly refresh your One K Defender helmet with a Replacement Liner!

Two shells of helmets make up all sizes. The base shells for the Defender are Medium and Large.

• Use a Medium size helmet with a Small or XSmall liner to change the fit to Small or XSmall.
• Use a Large size helmet with an XLarge or XXLarge liner to change the fit to XLarge or XXLarge.

Sizes: XS - XL

Liners for the One K JR helmets sold separately

Not compatible with One K Helmets with MIPS