Highly recommended for gymnasiums and other areas where abuse is severe.This super tough cover is designed to protect clocks, bells and similar instruments. The unit is constructed of 9-gauge steel wire with corrosion resistant polyester coating. The octagon, spiderweb like shape also helps this cover take tough knocks in stride. As all STI protective covers, this Stopper is backed by a lifetime guarantee against breakage in normal use. Because the unit is white in color, users report that their clock numbers are easier to see than with darker competitive guards. 10.5" Diameter.