High and low air pressure down-the-hole drill bits water hole:two 1. Deliver maximum energy to drilling bit, ... thread connecting chuck and cylinder of hammer.Size available:DTH bits from 85mm to 330mm. The main products are:1. Similar ... or equal DHD, COP and SD series hammers, our DTH bits range from 85mm, 90mm, 95mm, 100mm, 105mm, 110mm, 115mm 120mm ...