Material: TPR with Nylon Safety Sleeve Size: 140cm Color: Red Strength: Level 1 The tubes are made from TPR (Thermoplastic Rubber) which then has a soft nylon outer sleeve that covers the whole of the tube. The reason for this is that in the unlikely event that should the inner TPR tube break or snap whilst exercising, the nylon sleeve will restrict the amount of movement so to avoid any potential injury that the snapping of a tube may cause. Specifications of