Ideal for high-abuse, cold weather (CW option-down to -40°C), and wet location applications such as schools, security areas/prisons and parking garages. NEMA 4X option available for wet and hose-down applications. Clear, UV-stable polycarbonate cover is .130" thick to prevent cracking or breaking. Cover is secured with four stainless steel, Torx 120 tamper-proof screws with center pin. The typical life of the exit LED lamp is 10 years based on continuous operation. Self Diagnostics option: provides a 5 minute test every 30 days and 30 minute test once every six months. Dual voltage input capability (120/277V). Emergency Operation: Sealed, maintenance-free nickel-cadmium battery delivers 90 minutes capacity to lamp.