2022 Atomic Redster STI 70 Ski Boots NEW! Size 24.5-The Redster STI 70 LC is Atomic's most flexible race boot for teenage ski racers, but the only thing junior about this race boot is the cuff height, specially sized for shorter, skinnier legs. The Slim Race Shell makes it easier to flex than other junior ski boots – combined with a World Cup Liner, this is a boot that's ready to perform on the race course. Give juniors tons of confidence on race day, and let them feel like they're in the big leagues with the Redster STI.