Slate

In film and video work a slate known a board with two hinged sticks attached, also commonly referred to as a clapper or clapstick. The slate is used to record a scene number and sync point (via the clapstick) at the beginning of a shot. In general the term slate refers to any sonic and/or visual marking of media. In audio slates have been historically recorded on tape via tones or actual voice prompts. The idea is to allow someone to later identify a specific performance or cut. Tones are sometimes used because they can be distinguished at high rewind or fast forward speeds.