Last month I purchased a set of MICH Ranger Communication System made by MSA Sordin. Being a mil-spec headset, it didn't work with my civilian radio. Therefore I had to order a special PTT (Push To Talk) button with a built in amp circuit to make it work. I ordered one from www.talkingheadsets.co.uk. I have been in contact with Keith Foote, the manager of the shop and he assured me that it would work. So I went ahead and ordered one today.
Since I bought the headset secondhand, I also ordered a set of gel ear seals. It would be more hygienic to switch them out.