1964-1973. 35mm SLR camera. Through-the-lens (TTL) metering. First automatic-exposure SLR camera in the world. Also known as the Topcon Uni and the Hanimex Topcon RE Auto. It's one of the first auto exposure SLR cameras with TTL metering. It is usually bundled with a 53mm f/2.0 six element lens which is compatible with the UV lens mount. It has a Seikosha made shutter with speeds from 1s to 1/500 of a second with B. Flash sync is at 1/60 of a second. It features a needle based TTL center-weighted metering system using a CdS cell. The meter has a range of 5 to 18 EV at (ASA 100), settable to film speeds from 25 to 400 ASA. The shutter speeds in metered shutter priority mode can only use the red shutter indicators down to 1/8 of a second. It uses a 1.35v mercury battery no longer available but has a 1.35V Zinc-Air replacement MRB625. The film transport uses a single stroke film advance lever and a rewind crank with release button. Unlike most later-day SLRs, this camera has a leaf shutter, leading to a more complex exposure sequence. When idle, the mirror is down to block the film from exposure (like an auxiliary shutter), and shutter and aperture are wide open. When the shutter release is pressed, the shutter closes, the aperture stops down, and the mirror turns up. Once the mirror has moved, the shutter opens then closes. The mirror falls down back to block the light pathway as both the shutter and aperture return to their open idle positions. Most of the information here is from camera-wiki.org.