Metal lens hood made by HORSEMAN, compatible with 10mm, 20mm, and 40mm sizes. - Model: HORSEMAN Lens Hood - Sizes: 10mm, 20mm, 40mm - Thread Diameter: 81mm - Inner diameter of the base holder: 70mm (the ring with the HORSEMAN imprint) - Material: Metal - Application: For camera lenses I received this from a friend as a lens hood for a HORSEMAN 4x5 camera, but I'm selling it because I don't know its specific use. The exterior is very clean and shows little sign of use. Price reduced: ¥5000 → ¥3000 Thank you for looking.