This cassette tape was a high speed digital data pack for use with ADAM for the ColecoVision Family Computer System. This high speed storage tape (in its original box) stored 256k of data. The back of the box contains instructions on how to use the cassette tape and contains the following warning.
WARNING: NEVER TRY TO REPLACE A MOVING DIGITAL DATA PACK. DAMAGE WILL RESULT. NEVER TURN THE COMPUTER "ON" OR "OFF" WITH A DIGITAL DATA PACK INSTALLED.
Evidently, high speed data storage is not for the faint of heart.