Approximately 3" x 1.53" Tanker Proficiency Badge magnet.
Unofficial Tanker Proficiency Badge History:
“The ‘Tanker’ insignia was actually a proficiency badge awarded by the Commanding General of the 1st Armored Division. Since the badge was initially awarded, literally hundreds of different unit qualification type awards have been designed and worn. These badges are authorized by Major Commanders and must be removed from the uniform when the individual is transferred to another unit. Such insignia must be considered unofficial if they have not been approved by the U.S. Army Department of Heraldry.”
Smith, R., & Pelz, R. (1985). Shoulder Sleeve Insignia of the U.S. Army 1946-1976 (Revised Edition). University of Evansville Press.