An ETC Source Four Lens Tube – 10º is a narrow‑beam lens designed for long throw applications where tight control and precise focus are required. The 10º beam angle is ideal for isolating specific performers, architectural details, or scenic elements from far distances, such as balcony rails, catwalks, or front‑of‑house positions. This lens tube produces a concentrated, high‑intensity beam with sharp shutter cuts, making it useful for specials and highlight lighting rather than general washes. It fits directly into compatible Source Four ellipsoidal fixtures, allowing designers and technicians to achieve focused, high‑impact lighting while maintaining the reliability and familiar performance of the Source Four system.