1.Diamond bits 2.coal mining,many types 3.good price and ... and controlled straightness.4. Down the hole hammers and DTH button bits (Down The Hole Drilling)Offer ir hammers,DHD3.5,DHD340a ... .4mm, 25mm,30mm,33mm,38mm,etc.8. Blast furnace tap hole drill tools.(Rod, Cross type bits, button bits and X ...