• High quality product.
• Use your PSX joypad, Dualshock, or Dualshock2 on your MegaDrive or Mark III console.
• 6 button joypad emulation with Mega Drive joypad mode
• 2 button joypad emulation with Mark III joypad mode
• Automatic mode detection on Mega Drive console and Mark III console
• 2 levels of Turbo Fire on A, B and C buttons in MegaDrive joypad mode
• 2 levels of Turbo Fire on A and B buttons in Mark III joypad mode
• Analog function supported : use the analog stick to replace up, down, left and right buttons

* A few games does not support it.

More info here :
http://www.tototek.com/pio/main1/SUBMENU/PARTS/LINKS/OS/mdclassicconverter.htm