Garmin GPS 18x LVC 5m OEM, part number 010-00321-36.
For the complete specs, go to Garmin's website.
This particular 18x LVC was originally purchased from RailHead Vision Systems. They make fleet management systems. It came with a female DB9 RS-232 connector mounted on a PCB with a voltage regulator. The original power connector looked like a typical olive drab military connector. I replaced it with a Powerpole.
The GPS works great. I plugged it into my computer and a 12v battery and it came right up. I used it with APRSIS32 with no problem. I also updated it with the latest firmware. (version 3.80, 03/26/2012) The person I got it from said it had not been used.
$50.00 plus shipping.