The Edge 810, 800, 705 and 605 have an expandable memory slot into which a microSD* card can be inserted. This card provides the ability to install detailed mapping to enhance the device's internal basemap.
It is recommended a standard speed card, no larger than 32 GB, be used in order to get the best performance from the device. Class 4 to Class 10 is considered standard speed.
While considering memory limitations, another limitation is the number of individual mapping segments. Roughly 3,000 mapping segments can be transferred to the Edge 810/800 and roughly 2,000 mapping segments to the Edge 605 and 705.
The Edge will pick and choose which map segments to show when the map segment limit is surpassed. It is suggested to transfer additional mapping segments to another microSD card.
*While any brand of microSD card should work, Garmin has only tested more common brands such as SanDisk and Kingston.