1-API Surface-Set Diamond Bits/core bits 2-diomand core bit 3-impregnated tube bits 4- ... impregnated diamond bits due to drilling equipment limitations.TSP core bits are set with Thermally Stable Polycrystalline cutters, ... inventory costs to be much reduced.Size Available of core bits"Q" series:AQ,BQ,NQ,HQ,PQ ... EWG,AWG,BWG,NWG,HWGOthers: NMLC,HMLC,LTK48,LTK60,BGM,NGM,ADBG,TBW,TNW,0ATW,BTW,NTW,NXD3 ...