Sinodrills Chevron Drag Bits Chevron drag bit: three wings chevron drag bit, four wings chevron drag bit; Drag bits diameter: 76mm to 445mm; Drag bits thread sizes: 2 3/8¡± API Reg, 3 1/2¡± API Reg, 4 1/2¡± API Reg, 6 5/8¡± API Reg, etc;