This is a finder screen mask for the CONTAX 645 system. This listing is for the 44x33 sensor size, as shown in the first photo. (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 used by inserting it into the screen to provide a guide for the actual shooting area. Since it is difficult to obtain the manufacturer's genuine product, I made this myself. I realized that I could mass-produce it, so I made it by hand in the hope that it would be helpful to those who have the same problem. Please note that the material is sensitive to moisture and oil, so please be careful not to get them on it. When attaching the mask, hold it by the edges and handle it so that fingerprints do not get on it as much as possible. The second and subsequent photos are examples of how it is attached. You will receive two finder masks. It is designed to be hooked onto the protruding part of the frame on the back of the finder screen, or attached 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 fatal defects or incorrect sizes. Typical compatible models include: ・Phase One IQ140/150/250/350/P40+/P30+/P21+/P30/P21 ・Leaf Credo 40/ Aptus-II 6,8 etc.