... Strong cutting structure durability 4.Fast delivery steel tooth roller bitProduct Description:Size from 3 7/8 ... API Spec7-1 &ISO 9001: 2008 steel tooth roller bit 1>Cutting Structure The wear-resistance ... tungsten carbide hard facing on the tooth surfaces for steel tooth bit. 2>Gauge Structure Multiple gauge ... 609.6(24” )660.4(26” )Available models:Steel tooth(IADC code)111, 121, 131117, 124, 126, 127, ...