This is a fiber optic light ring for microscope fiber optic illuminators. It comes with a 35 (890mm) metal-sheathed light cable and a two-step 5/8 and 25/32 (16mm and 20mm in diameter) adaptive plug for connecting to a light source. The light ring has 2-1/8 (56mm) inside diameter and 3-1/8 (80mm) outside diameter. It is brand new in box. Its retail value is above $580. Features & Specifications: A Fiber Optic Light Ring for 150 Watt Fiber Optic Illuminator Providing Even Bright and Cool Illumination 35 (890mm) Light Cable 5/8 and 25/32 (16mm/20mm in diameter) Two-Step Adaptive Plug Ring Light with 2-1/8 (56mm) Inside and 3-1/8 (80mm) Outside Diameters Durable Metal Construction Manufactured under ISO 9001 Standards