1. A device used to place an identifier in front of the camera at the beginning of a take. When shooting double system sound in the days of film, the clapping motion and the clapping sound was used to synchronize the audio to the picture in post production. Timecode slates (that display the time of day or the timecode of the audio recorder) are often used for backup when automated methods of synching picture and audio fail (which requires decent audio recording on the camera to match the sound recording when timecode is not being used). 2. A good roofing material that can last well over a hundred years and will never become part of the landfill problem.