4" DHD340 COP44 Q40 DTH Hammer for Mining Water Well and StoneworkProduct Information-Name: 4 inch high air pressure DTH hammer for mining water well ... DHD350R,DHD360,DHD380,COP44,COP54,COP64,COP84 and QL40,QL50,QL60,QL80 hammers. DTH hammer is one of our main products.It ... durable for being produced with advanced craft-work and good material.Our 4" DTH hammer has features below: long working life, low ...