mj, this is a garmin 2010c i picked up for $500 w/o transducer. it came with the gsd21? sounder. i love it because i can see it. it is the first garmin i've had and it is easy to use. i am not to impressed with the sounder and not a fan of "all in one" units. i had plans to flush mount this on the dash and put a bottom machine where this is mounted. but that w as 3 years ago...