Info from Camerapedia
The name is sometimes spelled Zenith in English, such as the manuals published by the UK Zenit-importer TOE. However, TOE's imported camera bodies as from 1963 retained the "Zenit" badges. The early Zorki-based models before that time were labelled "Zenith" in a handwritten style of script. While frail and a technical improvisation they were the cheapest Pentaprism-SLRs in the UK at the time and are highly desirable collector's items today. In a way, they show a logical development Leitz should have taken decades before, instead of promoting their expensive and clumsy "Visoflex" attachment as an SLR-substitute.
The Zenit TTL is a Russian 35mm SLR produced by KMZ (Kraznogorsk) and BeLOMO from around 1977 to 1985. It was an upgraded version of the Zenit EM, adding stop-down TTL metering and a rewind crank in place of the knob.
The viewfinder is blue-tinted and comparatively dim and small (cf. the 'brilliant'-type Zenit E). The central portion of the viewfinder screen has a micro prism in the middle surrounded by a clear matte area.