A nut is a metal wedge threaded on a wire that climbers use for protection by wedging it into a crack in the rock. Quickdraws are clipped to the nut wire by the ascending climber and the rope threads through the quickdraw. Nuts come in a variety of sizes and styles, and several different brands are made by competing manufacturers. Most nuts are made of aluminum. Larger nuts may be threaded on Dyneema cord instead of wire