Product descripion of medium air pressure dth drill bit: Size:90mm Hammer: 3.5 inch Package: in wooden case Productivity: 2000pcs/month 1.Suitable for high pressure drilling rigs 2.Water well drilling 3.Record breaking penetration 4.Exploring Civil Engineering Applications 5.Lowest cost per foot drilled 6.Simple & robust design 7.Exploring Civil Engineering Applications 8.Foot Valve not required in the bit 9.Longer parts life 10.Maximizes efficiency 11.Develops greater power for any compressor capacities