Vivobarefoot Men's Hybrid M-M 100% Leather Imported Rubber sole Upper: Pull Up Leather: Vegetable tanned leather with abrasion leather and rip stop Nylon trimmings for increased durability Lacing: Lace-up System: Fasten securely with simple tie-up lace Collar/Panel & Lining: Woven Nylon & Polyester, Polyurethane Insoles: Removable: 3mm Pressed EVA Insole for additional thermal protection when necessary Sole Construction: Off Road: Rubber outsole specifically designed for off road surfaces with directional lugs to maximize surface contact for superior barefoot traction