The Altra Superior offers optimal protection and lightweight comfort for adventurous off-road running. This trail running shoe is built with a zero-drop platform, which provides stability while encouraging better running form. The removable Stone Guard system protects your feet from loose rocks. CheckerTrail outsole allows for ideal traction amongst the wildest terrains. A two-layer AltraBound midsole maximizes energy return, putting more bounce into your step. The foot-shaped design forms to your foot, enhancing your speed, and allowing for a comfortable fit. Wt. 8.9 oz.