10PCS Copper Sealing Ring Hex Head End Cap Plug M5 1/8 1/4 3/8 1/2 Male Thread Pneumatic Components Fitting Connector Adapter

10PCS Copper Sealing Ring Hex Head End Cap Plug M5 1/8 1/4 3/8 1/2 Male Thread Pneumatic Components Fitting Connector Adapter

Aliexpress UK