We are China supplier of TCI tricone bits and pdc diamond bits Size: 3 7/8"--17" API&ISO9001:2008 ... can supply rock bits,kingdream bit,smith bit,tricone bits, diamond bits,PDC bits,TCI tricone bits, steel tooth bits, milled ... 3-1/8” to 17”.There are different PDC (polycrystalline diamond compact) grades and shapes applied for rock formations as follows ... API 8-1/2" New PDC Bits/PDC Cutter/Diamond Bit