The Vitrex 33 8140 Contractors' Knee Pads are made from rigid nylon shell with removable inner padding. They feature a central hinge allowing pads to flex with the knee for more comfortable use. The knee pads are ideal for building work, laying floor tiles, carpet/laminate flooring, car maintenance, welding etc. They have a fitted ribbed section for excellent stability and thick, soft, breathable inner padding.