Andrew wrote:

Andy Burns wrote:

https://screwfix.com/p/stopcock-key/71652

It looks like it is designed for metal stop cocks, ones that
need some welly to turn on those blue-moon occasions when you
need to.

That is what I bought it for, but it works well on plastic stopcocks too.

A external combined water-meter/stop cock box wouldn't need
anything that strong, because the stop cock is plastic and only
turns 90 degrees, but the extra reach could be necessary.

My plastic one (2017 vintage IIRC) is multiturn.