... and regions who are trading or drilling contractors. We have very good reputation in drilling field.Available sizes: 60mm,65mm, ... 8mm(5 5/8”),149.2mm(5 7/8”)152.4mm(6”),155.5mm(6 1/8”),158.7mm( ... 8mm(10 5/8”),295.3mm(11 5/8”)311.1mm(12 1/4”),346.0mm (13 5 ... 2”),508mm(20”),558mm(22”),609.6mm(24”)660.4mm(26”)Available models: Steel tooth(IADC)111, 121 ... 737512,522,532,612,622,632,732Roller bit, roller cone bit