I'll start posting parts..
Headphones.. Peltor 105's .. Lowes or Home Depot 25.oo
Coiled cable you can use CB microphone cable, this one is 10 foot. so you cut it as needed, never to long.. then once cut you use a heat gun to put the strait end on ..
http://www.amazon.com/Replacement-MIC-CORD-Coiled-Workman/dp/B00AB2L3MG
http://www.mcmelectronics.com/product/111-1046&cid=prodCrossSell
M12 connector... Male
http://www.mouser.com/Search/Produc...tualkey52340000virtualkey523-12-08BMMA-SL8001
then the mate if needed.. female..
http://www.mouser.com/ProductDetail...=sGAEpiMZZMvf6myxbP4FpNM/SW8L7Vi1DaibbZ1g9dA=
then the gel pads, add a nice cushion for the ears, but if in the sun they will only last a few years...
http://www.aircraftspruce.com/pages/ps/head_ear/dregel.php
the cross over wire you can get at radio shack, I use a small round type with two wires, 24 gauge. Or speaker wire.
Heyco 3237 fitting for where the coiled wire comes into the headphone cup
http://www.mouser.com/ProductDetail/Heyco/3237/?qs=sGAEpiMZZMt5bLT1twLkep3x35n9WfZtMs50es7RH7U=
speakers I prefer the 2463's but you can shop for some Mousers site, I recommend a very low in put (power rating) of between .10 to .25mw ..anything above that will not be very loud... around 50mm in size.. Ohms .. the 2463's are 150 Ohms and work great
http://www.mouser.com/Electromechanical/Audio-Devices/Speakers-Transducers/_/N-awp4u?P=1yyy7x5