This is a single gooseneck fiber optic attachment for microscope fiber optic illuminators. It comes with a 22 (560mm) 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. Features & Specifications: A Fiber Optic Single Gooseneck Attachment for 150 Watt Fiber Optic Illuminator Providing Even Bright and Cool Illumination 22 (560mm) Long Light Cable 5/8 and 25/32 (16mm/20mm in diameter) Two-Step Adaptive Plug Durable Metal Construction Manufactured under ISO 9001 Standards