Tecnica Women's Diablo Sprint Trail Runner 100% Synthetic and mesh Rubber sole Oversized, rockered profile of the soles optimzes biomechanics and energy transfer. Exaggerating the heel and toe heights increases the percentage of sole that is rockered to increase energy transfer and reduce fatigue and stress Ultralight composite plate in forefoot provides push thru protection, forefoot stability and maximim propulsion Tenigrip outsoles feature triple density rubber composite for the perfect balance of traction in accellerating and decellerating conditions Super absorbing heel material and shape provide comfort and support plus energy transfer from heel strike to initate rolling Composite external heel wings provide lateral stability by locking heel into place