|We also make carbon fiber end pins both Solid and Hollow rods for double bass that are 1/2 inch in diameter and standard 16 inch length. These end pins have a sharp heat hardened tip with threads. To complete this end pin, we add a round rubberball with a specific density and a plastic threaded insert is screwed onto the end pin tip (see rubber ball and plastic insert below). Custom sizes are available for the solid rod bass end pins only up to 25 inches. Weight for the solid bass rod is 3.4oz and the hollow bass tube is 1.7oz including the tip.