The Optonica CP-9100 is a stereo cassette deck that was part of Optonica's product lineup in the late 1970s and early 1980s. It is designed to offer high-quality playback and recording of cassette tapes, and is noted for its compact and durable build. The CP-9100 features Dolby B noise reduction, which helps to reduce tape hiss during playback. It also incorporates a direct drive mechanism for improved accuracy and better tracking of the tape. The deck includes multiple playback speeds, allowing users to choose between standard speed and high-speed options. Additionally, the Optonica CP-9100 is equipped with level meters to aid in monitoring audio levels during recording, alongside various controls for fine-tuning audio output. The design includes a clean and functional layout, often appealing to users who appreciate a straightforward interface without unnecessary embellishments.