This combo kit includes 4mm plate foam, 2mm case foam with hotswap cutouts and 2 round 10mm plugs to fill the holes where the feet screw in.
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 CTRL HIGH PROFILE - a keyboard designed and produced by DROP (previously Massdrop).
** Important Information Regarding Foam **
Thickness on this current batch of foam is 4.2mm to 4.5mm, so fit will be a little tighter than normal. It still works great, it just requires a little extra pressure while soldering your switches in place.
I received the kit and promptly installed it without issues. It has improved the sound of the board. It doesn't sound hollow and echo-y. Would totally recommend.
Fit and finish was A+. Shipping was fast. For the the money this is easily one of the best mods you can do for you keyboard. Pings were almost non existent after adding the foam!