bobafett669
Active Hunter
I was sent this link by a fellow 501st member. It claims it is very small and can be worn on your wrist. So we might be able to open it up and modify it for helmet use since the RS ones are not available anymore.
http://www.audiosoundselectronics.com/specpages/specs_waistband_amplifier.htm
http://www.audiosoundselectronics.com/specpages/specs_waistband_amplifier.htm