https://sd2snes.de/blog/aboutFeatures:
SD/SDHC/SDXC support (tested up to 200GB; no exFAT support yet so SDXC cards must be reformatted using FAT32)
High quality push-push memory card slot
Fast ROM loading (~9MB/s)
Fast menu navigation
Directories are sorted automatically, no need for FAT sorting tools
High resolution menu (512×224) for adequate display of long file names
Real Time Clock
Supports ROM size up to 128MBit (96Mbit actually implemented as there are no larger known memory maps)
Automatic near-time SRAM saving to SD Card (while the game runs). Some limitations apply:
near-time saving is switched to periodic saving when a game is found to use the SRAM as work RAM.
Automatic saving is disabled when MSU1 is used. SRAM is saved on reset.
Enhancement chip support (see below for implementation status)
SuperCIC key (SNES CIC clone):
enables operation on unmodified consoles of all regions
supports software 50/60Hz switching on SuperCIC enhanced consoles only
Auto region patching: eliminates “This Game Pak is not designed…” messages regardless of 50/60Hz setting
Supports up to 16000 files per directory