I bought these for a flight simulator dashboard project. At around $1 per switch, 5 per pack, this is a lot. Haven't used them yet but they are a good size (for my needs) with a 10mm high and 15mm wide knob. The actual hole size you will need (and not listed on the page) is 19.5mm x 13mm. That should be all you need. I carefully measured with a caliper. After all, it is a momentary, normally open, non-blocking switch. This means that the power contact only occurs momentarily when you press (and