Descriptions:

The B50-72mm ring adapter easily screws onto the Hasselblad lens with Bay(bayonet) 50mm lens filter mount, and converts the thread size of your lens to the thread size of any other 72mm accessory (such as filters, hoods, flashes and lens converters).

• The ring is perfect way to use all filter sizes without buying new filters.
• Step up a size or two more, and you can simply use your old filters without spending more.
• This item is made out of Aluminum (black)
• Suitable for all lens with a 50mm(bayonet) - 72mm filter ring size
• A must have for the serious photographer