... rubber seal 3)used to drill low compressive strength API 8 1/2" Kingdream Newest IADC 437 TCI tricone bit1)used ... for oil filed, water well2)FOB 100~3000 USD3)metal seal or rubber seal4)used to drill low ... ",6 1/2",7 1/2",8 1/2",9 1/2",9 5/8",9 7/8",12 1/4",17 1 ... , HJ517G, HJ527G, HJ537G, HJ547G, HJ617G, HJ627G, HJ637G, HJ737G,etc. API 8 1/2" Kingdream Newest IADC 437 TCI tricone bit