I have a set of Nathan’s M5 train horns they have been sitting around for a few years not sure if they work or not I don’t have a enough air to push through them I’m asking 3500 obo u can text or email me with any question 954-445-4158 or hd2tone@gmail.com 
Still got it
Might want to try the new Horn and Whistle board Gabo … The M5 is a rare beauty but I doubt you’ll find too many people here who are hard core collectors willing to spend upwards of 3 grand on a horn - especially not without a sound clip or an assurance of how the internals are.
You didn’t give much info on the horns themselves, so if you do head over to the H&W board just be prepared to answer a stack of questions on their history, how you came to own them, what’s been done to restore them etc etc.
Thanks DBO