ELECAUDIO EC-4 End Caps Copper OCC For cable 4mm² (x10) - Audiophonics
MECCANIXITY Copper End Cap Pipe Fitting Sweat Plug Connection 25.4mm(1") ID for Water Pipe Plumbing, HVAC, Refrigeration System, Pack of 4 - Amazon.com
COPPER END FEED END CAPS STOP END 8MM-108MM PIPE FITTINGS/PLUMBING/COPPER PIPE | eBay