lighting fixtures, connector strips may provide low-voltage controls (e.g., via DMX512 and Ethernet taps), for moving lights and effects, as well as microphone jacks. Power is fed to fixed electrics from terminal boxes at the grid deck via multicable. Single and double-purchase cable cradles mounted to lift lines can be used to drape the multicable, prolonging its lifespan and reducing the likelihood of conflict with adjacent line sets or lighting instruments. Pantographs are also used to drape the multicable feeding dedicated electric line sets. Dedicated electrics typically employ truss battens (pipe over pipe) to facilitate cable snaking and to maximize lighting positions. In large professional theatres, such as the Philadelphia Academy of Music, an electric may take the form of a flying bridge (catwalk) that provides a walkable platform for electrician access to fixtures and effects. Flying bridges may also be used for followspot positions. Orchestra enclosure line set It is not uncommon for the ceiling panels, clouds, of an orchestra shell to be flown. Larger, multi-use theaters that must frequently convert the stage from a drama theatre to a concert hall often make use of the fly system in this way. Before being flown the cloud is pivoted to a vertical orientation to minimize the space it requires for storage in the fly loft. Focus chair line set A less common use for the fly system is the use of a focus chair system. This is a system where a small chair with fall protection equipment is suspended from a track that runs the length of a batten to which it is mounted. An electrician sits on the chair, and is flown out to the height of the electrics, to focus lighting instruments. Flying rig Flying rigs are used to fly scenery or performers in a more elaborate fashion than typical line sets. A flying rig typically allows horizontal as well as vertical movement by paying out individual lift lines to varying lengths and/or through the use of tracks. Flying rigs usually involve specialized equipment and techniques operated by a relatively experienced crew. Peter Foy is known for his innovations in manual flying rigs, especially those used in theatrical productions of Peter Pan. Automated flying rigs, which synchronize multiple point hoists, are becoming more common as motor control systems become safer and more sophisticated. Fire safety curtain A permanently installed fire curtain line set, though not used for productions,