so heres a little video showing a garmin 74XX series unit showing tv and movies from a a tv/usb/sd tuner av box kit we install here at regal.
this unit works on any system with video in
garmin - 741,751,74xx,76xx,80xx
Humminbird ION10, 12
lowrance, HDS 9gen2, hds12gen2, hds7gen3,hds9gen3,hds12gen3
simrad NSS, NSO, evo1 and 2
and more