This David Clark H10-
The headset is fully guaranteed for 2 years, parts and labor. A new headset will cost you $300 plus. You can get this one for much less and it is guaranteed. It will work in all GA airplanes, Cessna's to Lear Jets.
If you are not completely happy you may return it for a full refund.
Why buy a used headset of unknown quality when you can get this one worry free!