An ETC Source Four Lens Tube – 19º is a medium‑beam lens designed to provide a balance between focus and coverage at moderate throw distances. The 19º beam works well for highlighting performers, lighting scenic elements, or creating defined areas of light without being as tight as long‑throw lenses. It produces a clean, controlled beam with sharp shutter cuts, making it useful when precise shaping is needed while still covering enough area to be flexible. This lens tube installs directly into compatible Source Four ellipsoidal fixtures and is commonly used in theaters, houses of worship, and other performance venues.