Plug & Stop Fittings
A stop plug closes a G1/4 port you are not using. Radiators, reservoirs and blocks all ship with more ports than a given loop needs, and every open one is a leak waiting to happen.
Alphacool Eiszapfen is the main range: stop plugs and screw plugs in chrome and deep black, including 6 packs when you are closing a whole rad at once. Also in the family are pressure valves, which look similar but do something different, venting the pressure change a loop builds as it warms.
Barrow supplies plugs in black and silver, and Thermal Grizzly and Phobya fill in further options.
Match the plug finish to the rest of your fittings. Chrome and deep black next to each other on the same rad is the sort of thing you only notice after the loop is filled.
