Super simple and intuitive to install, the foams completely changed my Alt keyboard's feel and sound profile to hit the deeper, muted feelings and sounds. With these added in, it makes the keyboard feel so much more premium. If you're on the fence about buying and you have a legacy alt keyboard, I would recommend the purchase 100%, especially if you like the feeling of something less metallic-y and softer.
Does a great job at filling the hollow parts of the keyboard with perfect cut outs for each slot and holes, does help to create a foam/marble sound out of the keyboard but cannot stop the stiff sound of the integrated plate.
It fit very well and make the keyboard type experience better. I bought one to test and in the end I bought for all my others alt keyboard. This is my opinion. Some people does not see any difference.
Really excellent foam kit, totally changes the acoustics of the alt for the better
No more sproing, poing, ping, boing noises from the board. It really sounds solid and lovely now. I replaced a homebrew concoction of sorbothane and this sounds better. The cut outs were perfect, it was easy to install (you do have to pull all the switches, but not a giant deal), and it works. Very happy.