The purpose of this article is to list the maximum memory size of the Micro SDHC card for the Fluke-1773, 1775 and 1777.

The Fluke-1773, 1775, and 1777 have an internal memory of 8GB but if you want to increase the memory you have the option of installing a Micro SD card of up to 128GB. When you plug the Micro SD card into the meter it will automatically use the Micro SD card instead of the internal memory. 

Below is the picture of the location of the SD card slot with a red box drawn around it. You have to remove the battery door.