The magnetophone 65KL, which appeared in 1955/1956, is a portable unit in a plastic case, with half-track technology and a frequency range of 60 to 10,000 Hz at a tape running speed of 9.5 cm/s. Half-track technology means that only the upper half of the tape is recorded. After passing through, the reel can be turned to record the second track.
The KL65 has a combination head for recording and playback and an erase head. It can be equipped with reels up to 13 cm in diameter. The playing time is 2 × 45 minutes when using 260 m longplay tape. The unit measures 308 × 125 × 234 mm and weighs 7.2 kg. (Source: Wikipedia)