An emergency building entrance system (often called a Knox Box) is a secure key box or cabinet installed near a building’s main entrance that provides the fire department with rapid access during an emergency. Its purpose is to help responders enter quickly without forcing entry, which saves time, reduces property damage, and improves firefighter safety and coordination. These systems are especially useful for commercial buildings, apartments, schools, and facilities with multiple locked areas. Typical contents include master keys for exterior doors, stairwells, and interior rooms; elevator keys or override keys; fire alarm control panel or fire command center keys; access cards or fobs; and keys for roof access, mechanical rooms, and electrical rooms. Some boxes also include emergency contact information, building floor plans, and details on utility shutoffs or hazardous materials, depending on local fire department or AHJ requirements.