2mm thick EVA foam designed to be placed between a 3mm switch plate and Lily58 PCB.
This foam is not designed to be used with 1.5mm switch plate. The best way to determine if this foam thickness is right for your build is to measure the distance between the bottom of the switch plate and the top of the PCB.
Plate foam is great for changing the sound of the keyboard when typing. Sold in pairs. Enough for one full keyboard.