Vintage Advertising Sign electrical protection by. Watchman Supervision Sprinkler Supervision. Embossed tin metal small sign. Please view all pictures to see condition. Measures approximately 5 1/4″ by 8″. Speaking with someone with a long history of working in the alarm industry, they were able to give me the following information. The were owned by the Rose Family. Original location was W. Chicago and Wyoming in Detroit, Michigan. Bought by Guardian Alarm in 1983.