DX1: "The keys can be placed just about anywhere on the board you want them. There are no grids, hot zones, or marks of any kind that restrict where you place the keys, nor how far apart they are. The radio frequency system it uses operates at 13.56 MHz, and each of the individual keys is powered through inductive coupling. That means that you can actually hold the keys a very small distance off the surface of the board and they will still function."
