2 headsets with 2 jack plugs to connect them together.  I installed a test wire on the plugs to show wiring orientation.  You will need to put speaker wire or coax where the test wire is to the distance needed for your application. This will require soldering.

New out of box David Clark over the head dual muff headset.

These are not for pilot to tower communication. This has a single plug.

Voice powered headset with acoustic boom.  

Used to communicate where no power is available and also can be used in explosive atmosphere.

For noise up to 100db. 30 inch cord with single plug.