On your mark! Get set! Go! The tenth generation of the GEL-Noosa Tri series keeps the energy amped up to for avid runners and triathletes. technology Impact Guidance System design enhances the foot's natural gait from heel strike to toe-off heel clutching system/ WET GRIP sole rearfoot and forefoot GEL cushioning systems attenuates shock during impact and allows movement in multiple planes as the foot transitions through the gait cycle Propulsion System engineered for ultimate comfort construction nylon mesh/synthetic upper rubber sole with ASICS high abrasion AHAR rubber placed in critical areas for exceptional durability light weight solyte midsole sleek design with seamless construction and technical engineered mesh for sockless wear mono-sock fit details optional elastic laces and heel-and-tongue grips make transition a breeze