This listing is for a Garmin 4210 in great used working condition. The unit has been thoroughly tested and verified to be fully functional. We confirmed proper operation of the chart card slot, NMEA 2000, NMEA 0183 power, video input, and all network ports, all of which tested successfully. The unit has also been updated to the latest available software version, ensuring optimal performance and compatibility. In addition to the standard functionality checks, this unit has been professionally serviced to address common issues found in the 4000 series. The most frequent issue with the 4000 series is LCD degradation. This unit has undergone an LCD screen replacement, restoring it to its original clarity and brightness. These repairs have been completed before listing this unit for sale, ensuring it’s in top condition, ready for immediate use on your vessel. Please Note: During production, Garmin used two different styles of connectors for the Power, NMEA0183, and Video ports: (1) Full-Threaded connectors, where cables must be threaded onto the connection points. (1) Half-Twist connectors, which require a half-turn in the correct direction to ensure the connector is securely seated. This unit is equipped with Half-Twist Power, NMEA0183, and Video connectors. Please verify that your cables are compatible before purchasing.