item #FinderNo25. The thread on the right side are roughly 31.5mm in diameter. There is no lens on the right side of the finder. This is just the back half of a finder. The eyepiece is present. The mounting hole centers are 22mm apart. The white part of the tube is 22mm in diameter. Marks on the finish. The eyepiece has clear glass. The eyepiece appears attached to the tube. Condition 7-.