Multi-Threaded Self-Retaining U-Nuts, also known as Tapped Barrel U-Nuts, are primarily used in the automotive industry where extra strength is required. The strength of the tapped barrel u-nut is equal to the machine screw used. It allows single-wrench tightening of the thread assembly. In addition, some multi-threaded u-nuts are available in Free Spin or Prevailing Torque designs. This page displays Metric Thread X Pitch Sizes M6 X 1.00 for various panel thicknesses and an assortment of specifications to meet your application needs.