This is a yummy wide to tele finder designed for vintage RF cameras. Has the immense advantage of magnifying the entire field rather than just showing ever smaller framelines as the focal length increases. Plus it provides fine adjustment of field of view depending on distance of subject - see first photo!. Optics are crystal clear. Includes original bakelite case. All for a good cause: all proceeds including shipping charges will benefit our local community radio station, WCUW, broadcasting at 91.3 FM in Worcester, MA and also streaming at Buyer pays only actual shipping, which will be not much. Enjoy!!