Seat-belt grade nylon protects tubing from damage, drying out, and also stops whiplash in the unlikely event the tubing fails. Individual tubing is available in regular 48"L and 36"L ProTex™ Junior for younger and smaller students. ClassPlus™ Packs of ProTex™ tubing include our UltraFit™ Steel TubeMover™ Cart, and a set of 3 laminated UltraFit™ Resistance Tubing Charts.