There are only two authorized methods of making bumper numbers: using adhesive vinyl (stickers) and paint. United States Army vehicles must be marked with a unit designation to foster accountability and promote attention to detail during maintenance operations. The term "bumper number" refers the combination of numbers and letters on the front and rear of a vehicle. There are many regulations that govern the use of bumper numbers. These regulations serve to standardize markings across the army in order to improve efficiency and ensure markings add to combat readiness.