... is set with natural or synthetic diamond, and it is used to couple the drill bit with the core barrel. Its main function is to ... , EWT, AWT, BWT, NWT, HWT (Single Tube/Double Tube) WG Series: EWG, AWG, BWG, NWG, HWG (Single Tube/Double Tube) WM ... Series: EWM, AWM, BWM, NWM T2/T6 Series: T256, T266, T276, T286, T2101/T676, T686 ...