SiDE3

Yes, these are version 3.1

Abilities:

• Loads XEX, CAR, ROM
• Limited ATR support
• Occupies the Cartridge slot 
  
• Uses SD card as a HDD device
• On board Real Time Clock
• On board SDX

Features:

• Use of inexpensive, easily sourced SD cards instead of CF cards
• Emulation of a wide range of cartridge types, up to 1MB in size
• Real time clock with battery-backed NVRAM
• A massive 8MB of flash ROM and 2MB of fast SRAM
• Versatile ROM/RAM access with DMA engine
• Hot-swappable media
• Dual mode (SDX/Loader) operation, controlled by switch
• Menu button (doubles as ATR swap button when used with U1MB)
• Excellent build quality with stylish case design
• Go here for information: https://atari8.co.uk/firmware/side3/