Diopter correction lenses for the Mamiya RB67. A set of 4 lenses with diopters of -0.5, -3, and -4. - Brand: Mamiya - Model: RB67 - Type: Eye Correction Lens - Diopter Values: -0.5, -3, -4 New, unused condition. Two -0.5 lenses are unopened. The -3 and -4 lenses have been opened, but are new. Never used. Thank you for looking.