To prevent the spread of smoke and fire, fire barrier products, also known as fire stops, provide a physical barrier. Pipes and conduits can be temporarily sealed and plugged with firestop pillows, sheets, and wraps. Cracks and seams are sealed with firestop sealants, caulks, and putties. The use of firestop pipe collars and cast-in devices closes the openings left by damaged pipes. Electronics and electrical work are protected by firestop pass-through devices.