This drop-in iris for is a beam-shaping accessory used in Source Four ellipsoidal reflector spotlights to manually adjust the diameter of the light output. It fits into the accessory slot of Source Four fixtures and is operated via an integrated handle, allowing users to smoothly transition the beam from fully open to nearly closed. The iris is constructed with multiple tempered, heat-resistant metal leaves capable of withstanding temperatures over 1,000°F, making it suitable for high-intensity theatrical and studio lighting environments. Compatible with full-size Source Four ERS, Source Four LED, Source 4WRD, and ColorSource Spot fixtures, it is commonly used to create followspot-style effects or to refine gobo projections with greater precision.