One K Skull Cap Refit Liner Size:X Large and clip-on adjustable running attachment

and clip-on adjustable running attachment

but with some flex to it

waterproof HYDRO-Tx membrane prevents water from entering into the foot part up to the zipper

Matching running and standing attachments are available

One K Skull Cap Refit Liner Size:X Large and clip-on adjustable running attachmentIf a One K Helmet does not come in your size, you can easily change the liner for a perfect fit. Our liners also provide ultimate flexibility for growing children, shared helmets, or women who wear hair differently for schooling and show! Three shells make up all sizes. The base shells are Medium, Large and X Large. Use the Medium size helmet with a Small or X Small liner to change the fit of the Medium helmet into a Small or X Small. Use the Large