Type: Chevron and Step type Wings: 2, 3 and 4 wings Size: 3" to 24"Thread: 2 3/8, 3 1/2, 4 1/2, 5 1/2, 6 5/8 API Reg. PinDrag bit are manufactured from forged high quality alloy steel and premium tungsten carbide insert, plus state of art welding technology and multiple precision heat-treatment to provide highest penetration rate and longest lifespan at roughest condition