... of the products.Tapered Drill BitType --Chisel Bits / Cross Bits / Button Bits Diameter---28mm,30mm 32mm,34mm,36mm,40mm,42mm,44mmThread ... ) DTH Hammer---76MM /90MM /110MM 3) Face ShapeConvex---Suitable for soft rock ( less than 1033.5bar)Concave---Suitable for medium-hard ... . Integral Drill Rod---H19/H22, Diameter---20mm - 42mm. T51 Thread button bits