Altra Olympus 4 Men's Blue/Yellow Watch the trails tremble before you in the powerful Altra Olympus 4! This sturdy trail shoe received a complete makeover, with more cushion and traction than previous versions. Lock into the engineered mesh upper to stay cool on long-distance journeys. Get a grip on wet and slick surfaces with the sticky Vibram® MegaGrip™ outsole. A rounded heel design works with the InnerFlex™ midsole to improve flexibility. Move over mountains–the Altra Olympus owns the trail! What's New? Engineered mesh upper increases breathability and durability. Premium tongue design provides a comfortable, locked-in feel. Vibram® MegaGrip™ outsole delivers superior traction on any surface. Who's it for? Trail runners and adventure seekers who want a shoe with excellent traction and superior cushion to support every step. Runners who spend long hours on the trail and need protection for their feet. This shoe is for ultra marathons and 100-mile races. Shoe Technology Upper: Engineered mesh upper keeps your feet cool and dry extended training sessions. Protective toe cap with drain holes provides built-in ventilation. GaiterTrap™ allows you to attach gaiters for extra protection. Midsole: InnerFlex™ midsole technology uses grid-like grooves to increase flexibility and improve off-road performance. Zero Drop™ platform encourages low impact landings and promotes proper form. FootShape™ toe box lets your toes relax and splay, while the big toe remains straight for stability. Outsole: Vibram® MegaGrip™ outsole provides excellent traction on a wide variety of surfaces and conditions.