SIGN UTILITY WORK _____ 48X48 ACM B\O DG W21-7(1). This sign with the legend utility work is made of aluminum in diamond shape in orange color with black writing. It has a 3M brand reflective sheet and 3/8" mounting holes. It is perfect to be installed on poles, fences or walls. In addition, one of its differentials is that the product meets MUTCD specifications.