On the '63 scene, the 45 and 33 & a third rpm record are the prerecorded music standard. Reel-to-reel tapes, introduced back in 1954, are an esoteric medium used only by hard core hi-fi fans. Two new tape formats have just been introduced. The 4-track "Stereo-Pak" CARtridge shows great promise as a mobile music medium. The cassette, presently available only in West Germany, is a format for dictating machines and is not designed for music reproduction. It will become available stateside in 1964.