Product Details Mamiya Auto Extension Tube RB No.1 - Body Only Description This is a close-up ring for the RB67. The RB67 is already strong for close-up photography, but this allows you to get even closer. The extension length is 45mm. Condition There are few minor scratches from use, and it is in beautiful condition. The mounting ring and interlocking mechanism operate smoothly. I have already disposed of the RB system, so I cannot confirm its operation at this time. Although this equipment has few parts that break down, please understand that it is a junk item just in case.