The zipperless design provides excellent fit and heat retention, and grips even on rocky areas and golotas. This model is also supported by professional divers. 0.2 inch (5 mm) operon jersey; FIR (far-infrared brushed material); The front of the boot uses a unique stabilizer rubber. Strap keeper to prevent fin strap from slipping off your boots. 2 different sole patterns provide effective non-slip function.