Inov-8 Men's F-Lite 250 Cross-Trainer Shoe 100% Synthetic Imported Rubber sole Explosive power: the power heel is 40% denser than the forefoot of the shoe and with an 8mm heel-toe differential, the power heel provides maximum power and mechanical advantage when lifting weights. Explosive speed: the midfoot lockdown holds your foot secure to the sole ensuring the shoe will move fast with your every step. Agility: next generation meta-flex technology and optimal multi-directional flexibility moves with the foot forward or laterally. Unrivaled grip: 360 degree rope-tec system extended onto the shoe's upper delivers traction and durability on rope climbs. Versatility: while the denser power heel delivers maximum stability when lifting weights, the forefoot provides more cushion for shock absorption and protection while doing box jumps or running.