1.for water well,micro piling,geothermal, anchoring 2.reliable performance 3.long service life 4.easy to maintain 5.stable Usage1. excellent in water well, geothermal, micro piling and anchoring drilling.2.Drill holes from 105mm to 140mm.3.match to 76mm drill rods with API 2 3/8"REG BOX4. match to bits with COP44.DHD340A,Mission40,QL40,SD4,XL4 shanksAdvantage1, good sealing effect to prevent ...