Whick Key Needed For Drain Down Valves

[plumbandplumber]

Can anyone tell me which key I need to buy for standard drain down valves on domestic systems please. I have one of the valves in the link below, and two of the four ends have square holes. However, one of these is too small and the other too big. I'm fed up with faffing around with a pair of pliers.

Services Cabinet Key | Pipe Fitting Tools | NoLinkingToThis

 

[Tjdservices]

My services key fits them so maybe try a different supplier?

 

[PlumbBobBob]

I use a 1/4" drive socket, can't remember the size off the top of my head

 

[PlumbBobBob]

or a small adjustable

 

[lame plumber]

multi keys are fine but most docs are positioned carefully such that you cant get at them, so best tool is a pair of grips

 

[plumben]

personally i use my bacho, spent too much time wasted spinning them round trying to find the right sized hole

 

[Chalked]

Old but the best.
Isle of Man key.

Isle of Man Lockshield Radiator Valve Key - Plumbers Mate Ltd

 

[REDSAW]

4'' bhaco

 

[billybob150811]

8mm spanner or mastercool 70082 refrigeration wrench has 1/4 3/8 3/16 5/16 square holes