Check the listing for details. 5th ADA Battalion Crest DI/DUI CB S21 HM. Condition: Used. Listed at 3.25 USD. Insignia for the United States Army, 5th ADA Battalion. Clutch Back with S21 Hallmark on the back. A must for any serious ADA crest collector. This crest is in great condition for it's age. Very unique insignia that will stand out in any collection.