MillMax sockets are used to convert a solder PCB to a hotswap PCB. You’ll still need to solder them in, but in the end, you’ll have a hotswap PCB. They are more durable than Kailh sockets and you can use them to support multiple layouts. These are sold individually and we recommend ordering a small number of extra sockets. And don’t forget, you will need 2 sockets for each switch.