The Master System, often called the Sega Master System or SMS, is a third-generation home video game console that was manufactured by Sega. It was originally released in 1985 as the Sega Mark III in Japan. After being redesigned prior to its North American launch, the console was renamed Master System and released in 1986 in North America, 1987 in Europe, and 1989 in Brazil.

Technical Specifications
Processor: 8 Bit Zilog Z80 @ 3.5 MHz
ROM: Games can be up to 512K (banked), 8 Kb internal BIOS, up to 256 Kb ROM if game built-in
RAM: 8 Kb + 16 Kb video ram
Display: Television
Text display: Not Applicable
Graphics display: 256 x 192, 256 x 224 and 256 x 240
Colours: 32 Colours from a palette of 64
Sound: 4 Sound Channels (Mono)
Keyboard: Not Applicable
Interface: Unused expansion slot, game card slot, cartridge port and controller ports
Data Storage: Cartridge and Card Slot
Power Supply: External PSU
Software: Literally thousands of games available.

NOTES:- Please turn off system before removing/replacing cartridge