AtlasIED is a manufacturer of commercial audio, paging and intercom systems widely installed in schools, hospitals and other institutions. Its electronic bell tones are used with scheduled paging systems to signal the start and end of class periods throughout a building. Short recordings of those real system bells have circulated on soundboards and in video edits, where their authentic institutional sound works better than a generic ring. Editors keep using the clip because almost every viewer recognises the tone from their own school days.