If you hold your arm at your side in a natural position, then bend you elbow at a 90 degree angle without moving your wrist, you'll notice that your hand does not rest flat. The natural position of your wrist is angled, as if it was designed for handshakes! When you type on a flat keyboard, you have to force your hand flat to line up with your keys. This can be uncomfortable, especially after long typing sessions.
Tenting kits allow keyboards to be angled on your desk in order to better match the natural position of your wrists. Since everyone's tenting preferences are different, KeebMaker has designed modular tenting kits that allow the angle of each keyboard to be modified on the fly to fit any comfort level.