Sega's innovative 3D glasses are still the only 3-D glasses avaialable for a home console. When they are plugged into the Master System LCD shutters over each eye rapidly open and close at high speed allowing the the right eye to view the screen, then the left, then the right. The shutters are synchoronised to the game so the wearer gets a slightly different image in each eye, giving the illusion of a 3-D image.
The 3-D Glasses can only be used in the Master System 1 as the adapter needs to be plugged into the card port (not present on the Master System 2). The Glasses only work with the following games:
The 3-D glasses however were not a popular item due to thier price (£45) and the fact that they were only compatable with the 3-D games. Nowadays they are one of the rarer Master System peripherals and are highly saught after.