This is a Mamiya M645 No.1 Microprism Focusing Screen, designed for precise focusing in medium format photography. It shows minimal wear with no significant scratches or damage, indicating it has been well-maintained. Ideal for photographers looking to enhance their focusing accuracy, this accessory provides a clear and sharp microprism pattern for easy and precise focus adjustments. It's a valuable addition for both collectors and active users of the Mamiya M645 camera system.
