Meet the iKey AK-39: a rugged wearable keyboard designed to withstand harsh conditions. It has an integrated pointing device and green backlighting. The snap-on faceplate eliminates accidental key strokes. The AK-39 is designed to meet MIL-461 standards. It is available in a night vision compatible configuration.
The AK-39 stays around your arm conveniently and withstands use in harsh electro magnetic interference environments. More info is available here.