This is a finder screen mask for the CONTAX 645 system. As shown in the first photo, this item is for sensor sizes 48x36 (or 49x37). (The patterns in the second and subsequent photos are different and are for illustrative purposes only.) When using a medium format digital back, the shooting area of the sensor is smaller than the original film size. This mask is designed to be inserted into the screen to indicate the actual shooting area. Since it's difficult to obtain the manufacturer's original product, I made this myself. I realized I could mass-produce it, so I made it by hand to help those with the same problem. Please note that the material is sensitive to moisture and oil. Please be careful not to get these on it. When attaching the mask, hold it by the edges and try not to get fingerprints on it. The second and subsequent photos are examples of how it is attached. You will receive two finder masks. You can either hook them onto the protruding part of the frame on the back of the finder screen or attach them to the frame with thin strips of double-sided tape. Please understand that this is a handmade item, so please refrain from returns or exchanges except for critical defects or size errors. Typical compatible models include: ・Phase One P45+/P25+/P45/P25/H25 ・Leaf Aptus-II 5/7, etc.