Core barrel- single tube/ double tube/ triple tube NQ, HQ, PQ, NQ2, HQ3, PQ3 T2, T6, LTK NMLC ... , A, B, N and H. MLC Series Triple Tube Core Barrels:These triple tube core barrels are generally used for geotechnical purpose, designed ... soft formations. Available diameter size 35-146mm. Wireline Triple Tube Core Brrels:Wireline triple tube core barrels are generally required in broken, fractured ...