1. This is the portion of a follow spot that houses gel and levers to place them in and out of the beam of the light, thus changing the color of the light from the followspot. Pictured is one from City Theatrical, sold as an accessory to a SourceFour™ ERS. Attached is the boomerang from a Lycian 1275 Follow Spot. 2. The non-documented, long form of the term "boom," used when referring to any vertical lighting position with a single upright pipe.