GT415013 GP6520 aka 4157942 is a 3/8 H6 3BX BOTTOMING 2-3 chamfer DIN Length/Ansi .381″ Shank HSSE-PM GT415013 TFL tap, 1.53″ Reach 3.94″oal High-Performance Taps Victory Straight-Flute HSSE-PM Taps Through and Blind Hole PVD Thru- Coolant-Neutral/Straight Flute