Saucony has provided runners with a top of the line trail running shoe in the Xodus ISO. Now enhanced with ISOFIT system, runners can achieve a more personalized and adaptive fit. Traction has been improved even further with a PWRTRAC rubber that gives runners better traction than other rubber materials used in the past. Though still aggressive, this shoe provides an excellent ride to keep runners comfortable as they tackle tough trails.Upper: FLEXSHELL upper with DWR treatment provides protection against the elements. ISOFIT provides a dynamic fit system to natural foot movement. RUNDRY lining wicks away moisture to keep feet dry. Internal gusset construction keeps debris out. Midsole: EVERUNheel Insert provides a lively, resilient ride while providing continuous cushioning and enhanced energy return properties. 4mm offset enhances balance on uneven terrain. Removable insole.Outsole: Aggressive lug design provides excellent traction and easy cleaning after muddy runs. PWRTRAC Rubber provides 3x better traction that standard rubber.