This combo kit includes 4mm plate foam and 2mm case foam with hotswap cutouts.
Installation requires taking the board apart, putting the plate foam inside, slipping the PCB back into place GENTLY, putting the case foam on the PCB, putting the 'acrylic' (plastic) diffuser back into place, press all of the plastic plugs in tightly to hold everything together and then screw the top half to the bottom half.
These foams are designed to fit the ALT LOW PROFILE - a keyboard designed and produced byDROP(previously Massdrop).
** Important Information Regarding Foam **
If you select Black 4mm foam, you will be sent BLUE 4mm foam and Black 2mm foam. Black 4mm is currently unavailable and no estimate on when it will be restocked. The blue foam is the correct thickness and even more dense so should be considered an upgrade.