... service 4.adequate stocks,fast delivery 5.IADC 517 8 1/2" IADC 517 Kingdream hard rock drill bits HAS series ... 161.9mm(6 3/8”),165.1mm(6 1/2”)190.5mm(7 1/2”),193.6mm(7 5/8”),200.0mm(7 ... /4”)381(15”),393.7(15 1/2”),406.4(16”)444.5(17 1/2”),508(20”),558(22”),609.6( ... ,532,612,622,632,732Bearing Type:HJ(metal sealed journal bearing) HA (rubber sealed journal bearingNo- sealed bearingPacking & Delivery:Packing ...