0.251 - 0.375 Inch Grip 3/16 Inch Dia x 0.656 Inch Polished 1100 Aluminum Standard Flange Dome Head Blind RivetClosed End Rivets are used when a weather proof leak proof seal is needed. Its completely closed end design prevents liquids, moisture, air and other contaminants from entering the riveted hole and or the rivet itself. the Closed End rivet design guarantees the mandrel head is fully retained within the rivet. Aluminum Aluminum Closed End rivets are bright polished for aesthetics and to prevent oxidation. the Aluminum Rivet Aluminum Mandrel