STI-13120EG Universal Stopper, Surface Mounted, Integral Sounder offers excellent protection against physical damage (both accidental and intentional), dust and grime as well as severe environments inside and out. When used on fire systems, Universal Stopper is intended for areas where the incidence of false fire alarms from manual call points is high or has proven to be a serious problem. These covers are strong, and durable and will provide long-term protection for your access control call points. They also carry an IP56 rating, making them suitable for use inside or outside.