Produced from 1985[1] to 1987 by Mitsubishi Plastics, the cards are plugged into onboard cardslots or into compatible adapters.
Several versions of the format were created, including a rewritable one that allows new titles to be downloaded to a card.
Later, the Sega Mark III and the original Master System had built-in card slots.
The intention of the format was to provide cheaper distribution means than the more conventional game cartridges.
Similar but incompatible formats, also manufactured by Mitsubishi Plastics, were used by other computers and consoles: the Bee Card on the MSX, and the HuCard on the NEC PC Engine/TurboGrafx.
The cards are also compatible with the Tsukuda Original Othello Multivision, a licensed SG-1000 console and the SG-1000-compatible Pioneer SD-G5 peripheral.
A limited edition version of the Card Catcher was bundled with two games, Zoom 909 and Dragon Wang.
The games were also sold separately from the Card Catcher and allowed players to send away for a free adapter at the time.
The successor to the SG-1000, the Sega Mark III was released in October 1985 and was backward compatible with both SG-1000 cartridges and My Cards.
F-16 Fighter (F-16 Fighting Falcon in some editions) requires legacy hardware from the SG-1000 that is not included in the Mega Drive/Genesis, and is the only Sega Card not compatible with the Power Base Converter.
Sega promoted the My Card EP using flyers and newspaper advertisements and pilot tested it at Tokyo's Tamagawa Takashimaya Futakotamagawa.
Dealers were to install EPROM rewriting machines at retail locations, while users would bring their card and write other games onto it.