... bit(taper button bit, taper chisel bit and taper cross bit), thread bit( R thread and T thread), retrac bit and dth bit ... high air pressure and low air pressure dth button bit. (a) high air pressure: Cop, Br, HD, XL ... FACE and BUTTON designs for our products:Button bit insert types: Button typeApplications Spherical button l ... l Best suitable for medium to hard rockl 15,000-25,000 PSI (100-170 Mpa) ...