Fire barrier products, also called fire stops, provide a physical obstacle to prevent the spread of smoke and fire. Firestop pillows, sheets, and wraps temporarily seal and plug pipes and conduit. Firestop sealants, caulks and putties seal cracks and seams. Firestop pipe collars and cast-in devices close openings left by burned away pipes. Firestop pass-through devices protect sensitive electrical work and electronics.