YXQ 4mm x 2.5mm Pneumatic Polyurethane PU Air Stiff Tube 10M Black 10M/32.8Ft PU Air Tubing, 0.6"(4mm) OD, 0.1''(2.5mm) ID Strong elasticity, not easily deformed, folded without creases, excellent flexibility Light weight, small bending radius, high mechanical strength Wear resistance, tear resistance, 30-50 times that of natural rubber; Good aging resistance, 5 times that of natural rubber ; Good oil resistance, 15-20 times that of natural rubber Smooth body surface, low friction coefficient, bright color, good flame retardancy, non-toxic and harmless