For typing, a wrist rest is a bad idea. What you really need to do to relieve your wrist RSI is to put down the keyboard legs (Or even tilt the keyboard the other way), and move it to the edge of the table to force yourself to KEEP YOUR WRISTS ELEVEATED. That's the key there. Resting your wrists while typing bends your hands upwards, which is unnatural and very bad for your wrists. If you keep your wrists elevated, you should never need a wrist rest (for the keyboard, the mouse is a different story), and your RSI should be relieved.