... CORE BARRELS OVERSHOT HEAD ASSEMBLY WATER SWIVEL HOIST PLUG REAMING SHELL... China Drilling Geological Equipment ltd., is the main professional manufacturer ... ,NQ,HQ,PQ, T2, T6 etc. Diamond core bit, reaming shell & shoe bit (syn. and surface-set, PDC)4.Drill tool ... , outer tube & inner tube wrench, foot clamp,etc. the reaming shell BQ NQ HQ PQ, surface set and impregnated