BD DRILL produce the broadest range of hammers, bits, and related equipment. This means more choices for you. It means you can work with the strongest support network in the industry, regardless of yourequipment needs. It means that you can look to one reliable and time tested source for all your equipment needs.?The optimum range of hole size for blast hole drilling with DTH is 90 mm to 254 mm (3 ?"–10″). Smaller blast holes are generally drilled using top hammer, and larger holes generally use rotary machines.?In other applications, like foundation drilling, DTH hammers can be used with single bit in hole sizes up to . 750 mm (30″). With multiple hammer units CD (Cluster drills) drill holes up to 70″ or 1778 mm.Choosing the right hammer is largely determined by hole size and type of rock formation. Ideally, the size of the hammer should match the required hole dimension as closely as possible, leaving just enough space for cuttings to evacuate the hole.It is mainly featured in:1.The strong energy of single impact and the low energy consumption in rock crushing;2.The weight ratio of Piston and Bit almost Reaches 1:1 to provide long effective acting time, which leads to the improved efficiency in rock crushing and the extended service life of the drilling tool;3. A good performance in central air exhaust and cuttings discharge, which reduces the repeated crushing of rock;4.A check valve device is available to drill holes finder water.Our 5 inch DTH Hammer has different types of bit shank like COP54, DHD350R, HD55A, MISSION50, SD5, QL50, ETC. it is a ideal drilling tool which widely used in such industries relating to mining, quarry, energy, transportation, metallurgy, building etc. http://www.bddrillgroup.com/dth...r/5-inch-dth-hammer.html