Lightweight breathable materials for a '2nd Skin' fit and feel; Roomy toe box allows toes to spread naturally and comfortably; Ortholite performance insoles with long-term resilience and anti-microbial properties; Zip Foam midsole compound is springier than EVA and offers more rebound over the life of the shoe; Stack Height: 23mm (heel) / 20mm (forefoot); Heel to Toe Drop: 3mm; Weight: 7.8 oz (M9); Best for Gym and Training, Tempo Runs, Daily Running