The new kask rex is their first foray into the world of performance mountain biking helmets as the rex isn39t just a modification of one of their road helmets such as the vertigo or k10 as was the case in the past for the rex kask have taken what they have learned in developing elite level road cycle helmets and taken it to the off road world with technology such as their innovative in molding and mit processes featuring on the rex but also the 39octo39 fitting system as used on the p