Get underfoot protection on the trail, over rocks, debris, and tough terrain. Slip a removable StoneGuard™ insert into your trail shoes for a stable and soft underfoot feel. Made to fit into any shoe, this removable StoneGuard™ insert comes in a variety of size ranges designed to be cut to a desired size and inserted under any insole. The diamond-shaped plating allows for a stable ride throughout your run, along with flexible yet firm underfoot protection. | altra Stoneguard in Black, Size: Large