TheUmarex Rotex air riflecartridge filling adapter is a quick coupler used to charge a cartridge with compressed air, using a PCP pump or HP cylinder.
Umarex Rotex quick coupler - accessories for charging pcp windcheaters at Kolba store
The adapter dedicated to Rotex RM8/ Regin airguns allows you to quickly connect your airgun to an HP cylinder containing compressed air or a PCP pump. The quick coupler has a brass construction and a 1/8" BSP male thread.