Under Armour Spine Running Shoes synthetic-and-mesh UA Spine Chassis Technology - Creates an incredibly light, flexible feel without sacrificing support. Micro G Foam - Encapsulated within the chassis delivers unrivaled rebound and energy return. Breathable Mesh Upper - With seamless structural support across the midfoot and forefoot. Solid Rubber Outsole - Provides full ground contact and superior traction, whilst carbon rubber adds durability in the heel. Full Length Moulded 4D Foam Sockliner/Collar - Conform to the foot's exact shape, eliminating slippage.