Adjustable 2 "diameter extension from male M48 to female M48, with a sliding counter ring. Total length 16 mm, travel range 13 mm. Element particularly useful in setting the right distance for astrophotographic elements (flatteners, OAG, field correctors, etc.).
• overall length: 16 mm
• material: metal
• threads: male M48 (2 "filter thread) / female M48
• producer: GSO, Taiwan