The Akai 4000 DS is a reel-to-reel tape recorder manufactured by Akai in the 1970s. It was known for its compact design and user-friendly interface. The tape recorder featured a 2-track stereo system and could operate at speeds of 3.75 and 7.5 inches per second. It had basic playback and recording functions, along with controls for adjusting volume, balance, and bias. The Akai 4000 DS utilized 7-inch reel-to-reel tapes and commonly used in home audio setups for recording and playback purposes.