... -design impregnated with optimum parameters DIAMOND BITS AND REAMING SHELLS (CHINESE STANDARD) Double-tube Core Bit and reaming shell36, 46, 56 ... , 59, 60,66, 75, 91, 110, 130Single-tube Core Bit and Reaming Shell36, 46, 56, 59, 60, 66, 75 ... , 91, 95 DIAMOND BITS AND REAMING SHELLS (INTERNATIONAL STANDARD) Diamond BitBQ, NQ, HQDiamondReaming ShellBQ, NQ, HQ Diamond Drilling Bits and Reaming Shells