Those are mine in a Sccobymania pod. It sits on the base of the oddment tray, and you have to cut out the holes for gauges yourself, 52mm or 60mm. Scoobymania WILL mark the centres for you though if you tell them what size gauges.
Mine were cut undersize with a holesaw, then sanded CAREFULLY to give a tight push fit to the gauges. That's all that holds mine in, and they haven't budged in 4 years.
The pod is held onto the oddment tray with two small blobs of clear silicone, although it too is a tight fit. I used silicone as it did slip once when I did a quick take off from some lights

before I glued it. You can't see the silicone once it's in place.
If you need to, it can be pulled off without damage to the pod or the tray, I know: I've had to do it. The silicone can also be removed from the tray with silicone eater.
Alcazar