Double Socket Arm with Two 2.5 Inch Round BasesThe RAM-101-G2U consists of a double socket arm and two 2.5" diameter round bases with the universal AMPS hole pattern. Designed into the mount is a 1.5" diameter patented rubber ball and socket system with adjustment points at both ends of the double socket arm. With a twist of the arm knob, you can move the RAM-101-G2U mount to your optimum viewing position.This mount is designed to hold the following devices: Garmin Fishfinder 120 Garmin Fishfinder 140 Garmin Fishfinder 250 Garmin Fishfinder 250c Garmin Fishfinder 340c Garmin Fishfinder 400c Garmin Fishfinder 80 Garmin Fishfinder 90 Garmin GPSMAP 172 Garmin GPSMAP 172c Garmin GPSMAP 178 Sounder Garmin GPSMAP 178c Sounder Garmin GPSMAP 292 Garmin GPSMAP 298 Sounder Garmin GPSMAP 420 Garmin GPSMAP 420s Garmin GPSMAP 421 Garmin GPSMAP 421s Garmin GPSMAP 430 Garmin GPSMAP 430s Garmin GPSMAP 431 Garmin GPSMAP 431s Garmin GPSMAP 440 Garmin GPSMAP 440s Garmin GPSMAP 441 Garmin GPSMAP 441s Garmin GPSMAP 450 Garmin GPSMAP 450s Garmin GPSMAP 520 Garmin GPSMAP 520s Garmin GPSMAP 521 Garmin GPSMAP 521s Garmin GPSMAP 525 Garmin GPSMAP 525s Garmin GPSMAP 526 Garmin GPSMAP 526s Garmin GPSMAP 530 Garmin GPSMAP 530s Garmin GPSMAP 531 Garmin GPSMAP 531s Garmin GPSMAP 535 Garmin GPSMAP 535s Garmin GPSMAP 536 Garmin GPSMAP 536s Garmin GPSMAP 540 Garmin GPSMAP 540s Garmin GPSMAP 541 Garmin GPSMAP 541s Garmin GPSMAP 545 Garmin GPSMAP 545s Garmin GPSMAP 546br