Piece of tape spliced beginning (head) to end (tail) for continuous playback or recording. To fold around. A loop/slack section of film with the necessary “play” to allow film which had been previously and continuously moving from a reel to be intermittently moved through a grate/projection head/optical lens arrangement. Proper loop size is important in threading a film projector, i.e., in telecine for film to videotape transfer.