... circulation drilling. down the hole High Pressure RC Drilling bit Bit for down-the-hole drilling, air reverse circulation drilling in ... water well drilling, geothermal well drilling, reverse circulation drilling.Bit Front designs:Complete compatible to be used with DHD hammer ... etcConvex Front, Flat Front, Concave Front, Concave DGR Front etc.Bit Dia. 85mm, 90mm, 95mm, 102mm, 105mm, 115mm, 133mm, ...