CRC Smoke Test is an aerosol spray used to test the functionality of a smoke detector. It not only checks if the batteries are working, but it also tests for obstruction or debris that may clog the detector vents. Packaged in a convenient, easy and safe aerosol. Safe for use on Photoelectric and ionization type detectors. Sound Effects provided by freeSFX: www.freesfx.co.uk Music Provided by Getty Images: juqboxmusic/Vision/SoundExpress/Getty Images Deep Blue Music/Thriller Riser 7/SoundExpress/GettyI mages