Plate foam is great for changing the sound of the keyboard when typing. Sold in pairs. Enough for one full keyboard.
Please note that there are many different configurations when it comes to switch plate thickness and switch heights. In order to determine the best foam thickness, a measurement should be taken between the bottom of the switch plate and the top of the PCB with keyboard switches installed on the keyboard.
2mm - Most often used between a 3.0mm Switch Plate and PCB with MX Switches
3mm - Most often used between a 1.5mm Switch Plate and PCB with MX Switches