The Vanish-R racing flat from Altra Footwear is light and flexible for a free feeling. Predecessor: None. Support Type: Neutral. Cushioning: Light, flexible response. Surface: Road. Differential: 0 mm. Altra Zero Drop recommends that those new to natural running and zero-drop footwear transition slowly by wearing these on shorter runs and gradually building up to regular mileage. Ideal for running, racing, and speed work. Designed to improve running form, toe splay, stability, and power. Breathable, engineered knit mesh upper. Lace-up closure. FootShape toe box allows the toes to relax and spread naturally for optimal comfort, speed, and stability. Lightly padded tongue and collar. Breathable DriLex fabric lining offers a great in-shoe feel. 6mm contoured foam insole. Zero Drop construction places the heel and forefoot at the same distance from the ground to encourage natural, low-impact running form. Durable, exposed, springy EVA midsole with Propel Plate TPU Propel Plate offers maximum energy transfer for maximum propulsion. Foot Pod Technology consists of an outsole and midsole layout that maps the foots bones and tendons for more natural flexibility. All rubber outsole for traction and shock absorption. Total Stack Height (total thickness of midsole and outsole underfoot): 14mm Last: XC. Imported. Measurements: Weight: 5 oz Product measurements were taken using size Mens 9.5, Womens 11, width Medium. Please note that measurements may vary by size. Weight of footwear is based on a single item, not a pair.