Developed specifically for technical and professional divers, the XT-Tech QD hoses have a smooth outer layer and reduced flexibility compared to the Xtreme hoses. The smooth outer surface prevents abrasion around the neck, less flexibility and negative buoyancy allow the longer hoses to stay in place. Outer polyester layer has Kevlar yarn reinforcement to make the hose stronger and more durable. Lighter in weight than traditional rubber hoses. End fittings are made of sea water resistant electroless nickel plated brass. Like all Miflex hoses, they are 100% leak tested and produced on fully automated assembly lines. Inner liner is made from polyether-based polyurethane, not PVC, as found in lesser-priced imitators. Approved for use with up to 40% oxygen. Hose is available in lengths from 9" to 32" (22.9cm to 81.3cm).