The Garmin Dashboard Disk is used to attach a Garmin suction cup mount (not included) to the dash. It is compatible with Quest, iQue M3/M5, StreetPilot i2/i3, and iQue 3200/3600 suction cup mounts. Note: For the Garmin Quest, measure the suction cup to see if you need the 2.6-inch or 3.5-inch disk. This product includes both sizes.