Material: Aluminum-Magnesium Alloy 535Finish: MillI.D. Size: 1-3/8"Pipe Size: 1"Set Screw Size: 3/8"-16 Thread X 1/2" LengthHex Key Size: 3/16"Can Be Used With Any Pipe Including Aluminum, Galvanized Steel, Stainless Steel And Black IronJoins Two Pipes To Continue A Straight LineGreat For Interior Or Exterior RailingsHigh Corrosion Resistance