The Altra HIIT XT 1.5 continues on the success of Altra's original cross-trainer with fresh colors and an improved upper. Designed with CrossFit and HIIT workouts in minds, it features a wrap-around sticky rubber outsole for rope climbing and lateral traction. More cross-training specific features include the removable insole- without it the stack height goes from 24mm to 18mm- stitch 'n' turn stitching underfoot for a comfortable fit with or without the insole, and the stylish, durable upper. Built to perform, the HIIT XT is the perfect choice whether you want to hit the gym or run a lap (or both!). Experience the new shape of strength.