... series Wire-line Double Tube Barrel Core barrelCore Barrels include single tube type,Website:http://www.yikuangdrilling.com, double tube type and triple ... series: RWT, EWT, AWT, BWT, NWT, HWT(Single Tube, Double Tube) WG series: EWG, AWG, BWG, NWG, HWG(Single Tube ... 275mm Russian standard: 59, 76, 93, 112, 132, 152 mm Double tube surface Size(surface exploration drilMetric system(mm)Imperial system ...