What is a double ended radiator key?
The parts of a double-ended radiator key are:
A double-ended radiator key has a 10mm square on one end for installation of 1/2 inch air vent plugs and half-inch blanking plugs.
A blanking plug simply plugs, or blanks off, one of the top two tappings - internally threaded holes into which valves can be fitted - of a radiator.
The square end is often described as a 'machined' end. 'Machined' means the square shape has been made by milling the end with a machine, rather than it being cast or moulded in that shape.
The other, hexagonal (six-sided), end of the double ended key is for the installation and removal of radiator valve tails which have a hexagonal (six-sided) internal shape.
Some radiator valves have internal lugs - small projections like studs that provide the grip for a spanner. The double-ended key has grooves along its valve-tail end for the removal of this kind of tail.
For step-by-step guides to using this and some other keys, see:and
This key is usually made of high tensile steel which is galvanised or zinc coated for corrosion protection.