G1 / 4 plug with O-ring
G1 / 4 plug with O-ring for sealing a screw hole.
With a reservoir with 6 screw holes, you only need 2 screw holes for mounting 2 hose connections. The remaining 4 screw holes can be used for lighting modules or temperature sensors, but if you are not using them, you can seal the holes with this plug.
These plugs are also used with video card blocks that support SLI / Crossfire.