The Goodson Tools and Supplies 3-D Fast Cut Ball Head Tool Body for Sunnen Insert Holders is designed to be used with .375" top pilots, giving the machine shop access to a wide range of pilot sizes. The Ball Head is for use where the Sunnen SGM-1025 would be used and will fit Sunnen Insert Holders SGM-1045, SGM-1055, SGM-1090, and SGM-1115. The tool holder channel is .500" and measures 3.350" long by 1.162" diameter.