Tom,

Thanks for posting the link to the video. I also got my helmet from E-Bay, in very good condition. After limited success in converting it to GA, I got help from the people at Pilot Avionics at their booth at AirVenture. Very helpful and it works just great. It is important to note that the Army always required (and still requires) ear-plugs to be worn with the flight helmet (same for tank crew helmets.) As a result, the SPH series may not have all of the hearing protection you might be looking for. As Wes noted, ANR can fit into earbuds today, so if you are getting a used (or preferably new issue from old stock) military helmet, you might think about that.