Different plugs
Helicopters use a single fat connector for their head sets vs. the standard two plug setup the rest of aviation uses. The internal electrical impedance is also different for helicopter sets. I would recomend the standard setup so that other folks headsets will just plug-in to your system. As a person with limited hearing myself, I would recomend for fixed wing recip powered aircraft, the Lightspeed Zulu and the Stratus 50D. The Zulu being quiet, light, and smaller of the two and the 50D being unbelievably super quiet but a little bulky. Here in Alaska our local avionics/pilot shop will loan out for a week or so any headset they sell. If your local shop has a similar policy try befor you buy, to find out what works best for you, is definatly the way to go. Remember all ANR technology is not equal, all are enginered to cancel a specific noise signature ie turbine, helicopter, or recip. and a system that works great in one environment may not in another. Good luck, Russ