I have other items for sale, so I will offer a discount if you purchase multiple items. Thank you. Function: Used to attach filters or conversion lenses that are larger than the filter diameter of the lens. Size: This is an adapter that allows you to attach a 77mm diameter filter to a 67mm diameter lens. Features: Precisely machined from aluminum material, it can be securely attached to lenses and filters. Usage: If you have multiple lenses, you can share expensive filters.