... tube/ triple tube NQ, HQ, PQ, NQ2, HQ3, PQ3 T2, T6, LTK NMLC, HMLC, NX NW, HW, PW, NWT, HWF ... the need to couple and uncouple the rod string each time the core is retrieved. Available sizes in AQ, BQ, ... . Available in diameters 46, 56, 66, 76, 86, 101mm. T6 Series Double Tube Core Barrels:These are a continuation of ... } ); } )(); Core barrel assembly NQ, HQ, PQ, NQTT, HQWL, T2, T6, NMLC, HMLC