.6mm square belt used for replacement, tape sounded good when tested (no warping or tapping sounds and timing appeared good). When I replaced the belt there was some residue from the old belt. I cleaned this residue off and forward play mode sounded good but reverse mode was muffled. After additional cleaning reverse play mode sounded better. Please be aware that this is an old unit with many small parts and will eventually require servicing to make sure the quality is maintained.

The recording functionality appeared to work since it recorded blank sounds over the cassette when tested, it just didn't pick up my voice because I don't have a wired microphone to for testing.