The R4 DS Cartridge is the current top-of-the-line in DS SLOT-1 flash carts. It is just an amazing little device like original DS cart size, it is a complete solution with no need to purchase any additional components or deal with any messy software and truly the easiest media enhancer you have ever done; To simply put it, this is a must have peripheral for any regular DS/DS lite owner.
The box includes: R4 TF Micro SD Adapter; USB MicroSD card reader/writer; Protect case; Manual CD.
Features:
2nd generation storage device (no booting tool required)
Flush fitting slot 1 card
Uses MicroSD card, FAT16 or 32
Supports any MicroSD card speed with no lag in game
Supports Clean ROM, drag and drop. Works on any OS
Built in NoPass
Automatically detect save type
Save directly to MicroSD card, not to onboard chip
Supports Moonshell and other homebrew. Open I/O interface
User friendly skinnable interface. Touchscreen or button operation
Supports rumble pak and memory pak
Supports the WiFi game, DS Rumble Pak, DS Browser
Supports changes of the background of Operation Interface
Support Skin DIY by setting background and font colors on Main Menu and Game Menu manually and automatically
Supports 4-scale-lightness adjustment ( DS Lite only )
Supports the Soft Reset.
Supports Action Replay cheat
Source: The Developer Website.