Plumbsure White Radiator valve spare, Pack of 3

Cheap and nasty...unusuable ...a total waste of money.........

Don't bother. They are cheap and nasty and do not work. When you try to tighten them they either slip off or snap, very frustrating.

If you are too heavy handed you will end up breaking them but for the money they act as a quick and cosmetically pleasant radiator cap. Not sure B&W do another version but I would look elsewhere if I need this again.

I returned them today as they are useless. If you tighten them to hold them on they break. If you don't tighten then then they fall off. Do not buy them.

There's no instructions on the packet or internet.
These work by placing the caps on the valve spindle and then - important - turning the top screw to make the little vice like plastic cramps inside the cap, grip the spindle.

It doesn't tell you this anywhere so of course, the first assumption is that they won't fit and are too big. Do not under any circumstances inspect the inside of the cap closely as they will fall to bits and the little spring loaded cramps are near impossible to rebuild.

They are simple to fit if you know the tip of putting them on and turning the top screw to increase the grip rather than secure the cap which is counter intuitive if you're replacing the kind that grip snuggly and the screw is used to secure rather than to grip.

Very simple if only they told you how they work on the packet rather than telling you there are two types and talking about replacing valves.