... and bit life Impregnated casing shoes can be manufactured in all series and varying impregnation heights Surface-set Casing shoes are used ... in various overbruden formations.Size Available:Q Series: BQ, NQ, HQ, PQW Series: RW, EW, AW, BW, NW, HW, PW, SW ... , UW, ZW, HWT, PWT, BWS, NWS, HT, PT, SZMetric Series: 46, 56, 66, 76, 86, 101, 116, 131, 146X ...