... tight tolerances and controlled straightness.4. Down the hole hammers and DTH button bits (Down The Hole Drilling)Offer ir hammers,DHD3.5 ... ,DHD340a,DHD360,DHD380,and low pressure hammers CIR65a, CIR90, CIR110, CIR150,CIR170etc,DTH drill bits ... :60mm-254mm bits with flat face, concave design fit for the atlas copco and ...