Heliopan 312 Adapter 67mm to Bay 6 Step-Up Ring (700312) Provides photographers with an efficient solution for using one set of filters across different lenses with different thread mount sizes, which saves photographers from needing to buy multiple versions of the same filter Made from high-quality brass, which means it will keep its shape and not warp over time like aluminum. Brass is also more resistant to side impacts and will not bind to lenses after prolonged use The ring is finished in matte black to prevent reflections when it is paired with a filter. It is best to use Heliopan branded filters to ensure that reflections and glare are kept to a minimum Allows 67mm filters to be used on Bay 6 lenses Made in Germany from only the highest quality materials