Telex 850

[LaidOffAgain]

Looking at purchasing a Telex 850 and when I was looking online they offered 3 models. One at 300 ohms, one at 600 ohms, and not sure what the 3rd was. Without pulling out my HS science books, can anyone give me the quick and dirty on these 3 headsets. Also please keep your answers to junior high level. haha Thanks for your help! LOA

 

[8v8ter]

I have the 850, but I don't recall having to choose among those options. Good thing because I don't know the difference. Mine works great in the 737 though.