Atomic Redster STI 90 LC 2025While the Atomic Redster STI 90 LC is for lighter junior racers, the only thing junior about this race boot is the cuff height, just a little bit lower for younger legs. Atomics World Cup liner tech make sure its got great feel and a precise connection between liner and boot shell. The Slim Race Shell makes it easier to flex than normal junior race boots. Power Control lets racers adjust both the forward lean and the precise stiffness of the boot