From back of the box
Advanced Control For The Advanced Player.
SEGA's advanced CONTROL STICK puts precise controlling in the palm of your hand. Developed to improve your skills, thus achieve higher scores for more excitement in video games.
From front of the box
A CONTROL STICK FOR THE SEGA MASTER SYSTEM.
Compatible with Commodore VIC-20, C-64, Atari 400, 800, 2600.
Also compatible with Commodore Amiga, Atari ST and possibly also SEGA Genesis/Mega Drive, and others