Casing/Rod shoe bits are used to fix the rods and casings in overburden drilling hole. The inside wall is smooth and large enough for free passage of coring drilling string.
Wireline Series: BQ,NQ,HQ,PQ,RW,EW,AW,BW,NW,NWT,HW,HWT,PW,PWT,SW,UW,ZW,NT,HT,PT,BWS,NWS,SZ,BTW,NTW,HTW
Metric Series: 46,56,66,76,86,101,116,131,146
X Series： RX,EX,AX,BX,NX,HX,PX,SX,UX,ZX