Mini-Cassette

Mini-Cassettes are Transformers from the Generation 1 continuity family.

Mini-Cassettes (also known as Cassette Warriors or simply Cassettes) are Transformers whose alternate mode is an audio cassette. They can fit into the chest compartments of Blaster or Soundwave (while the toys can fit into either, in fiction they stick to the communicator of their own faction).

Many of the characters have communication or espionage roles.

Japanese name: Cassettebot (Autobots), Cassettron (Decepticons)

From Teletraan I: The Transformers Wiki, a Wikia wiki.