The Nikon NIKKORMAT FTn Prism 23F3b-64-1 is a replacement part specifically designed for Nikon NIKKORMAT FTn film SLR cameras. This battery cover serves as a crucial component for maintaining the functionality of the camera, ensuring that the unit continues to perform at its best. Made by the trusted brand Nikon, this prism unit is compatible with the Nikon NIKKORMAT FTn series and is a reliable choice for those looking to repair or upgrade their camera.