Nut Insert, Rubber, Clorophrene, Finish Protective Powder, Thread Size 1/4-20, Length 0.829 In, Grip Range 0.031 to 0.187 In, Hole Size 0.500 In, Head Dia. 0.740 In, Body Dia. 0.500 In, Package Quantity 10 Well-Nut Threaded InsertsFlanged chloroprene bushing with a molded brass machine nut into 1 end. Seals against moisture and gases. Helps prevent galvanic corrosion. For isolating against shock-and-vibration, and electrical conductivity. Removable.