1/4" Diameter Shank, 0.425 to 0.575" Grip Range, Steel, Countersunk Head, Multi-Grip, Structural Break Stem, Rivet Rivet Type Multi-Grip, Structural Break Stem Shank Diameter 1/4 Inch Head Type Countersunk Recommended Hole Diameter 0.261 to 0.276 Inch...