The switch does not go easily into a 20mm hole, it had to be filed slightly larger. Not helped by a small piece of plastic on the side of the switch that had to be trimmed off with a craft knife. The other (green lens) switch was fine. Concerned that it gets warm when left on, suggesting quite a current draw - maybe the illumination is too bright.

The switch is fine, but the internal LED is white so when the switch is on it’s not a very convincing blue. A shame they didn’t put a blue LED inside or a stronger blue colour in the cover; I’ve put it next to a green switch from a different supplier that does look more convincingly green when it’s on. I can live with it!