Maintenance Airframe; Maintenance Powerplant
Other / Unknown
Deviation / Discrepancy - Procedural Hazardous Material Violation; Deviation / Discrepancy - Procedural Published Material / Policy
General None Reported / Taken
Human Factors
Was returning part to ZZZ that wasn't used on aircraft.  Box was closed with no dangerous paper work on it and didn't realize it was hazardous.  It was a Flight Control Unit and didn't know it had a battery in it. Cause: box was closed up and sealed and nothing to alert me that it was hazardous. It was a Flight Control Unit and didn't know it had a battery inside. The part had a [maintenance software company product number] and at the time of the occurrence we were not able to get into [company] software to receive part. Suggestions:  [cargo management system] should have a space to put the part number that you are shipping so if it is hazardous it should be flagged as hazardous.
Airline Maintenance Personnel reported aircraft part erroneously shipped in unlabeled container.