... drilling. down the hole High Pressure RC Drilling bit Bit for down-the-hole drilling, air reverse circulation ... geothermal well drilling, reverse circulation drilling.Bit Front designs:Complete compatible to be used with DHD hammer DHD330, DHD340, DHD350 ... , DHD360, DHD380, SD18, N180 etcConvex Front, Flat Front, Concave Front, Concave DGR Front etc.Bit ...