The Simplex 4903-9101 DC Strobe Plate was introduced in the late 1980s and discontinued in the mid 1990s, but in that short time frame it became a very common visual notification appliance to find in many schools throughout America. It is the strobe version to the 4903-9001 incandescent variant, and produces 4.75 cd compared to the .5 cd of the incandescent, making it almost ten times as powerful. It is commonly paired with horns, bells and speakers from the 2901 and 4901 series, the most popular combination being the 4903-9101 strobe plate with the 2901-9838 horn.   

There are multiple units available, and the unit you receive will be of similar quality to the unit pictured in this listing. All units have been tested, cleaned, and will be shipped safely.