This filter was purposed originally for 75mm lens of turret Konvas. But it can be used on other lenses that have 45x0.5mm filter thread - for example, on 50mm lens of turret Konvas. Take note that if will fit old lenses only (RO series made at KMZ). Later LOMO OKS lenses have different thread.

Used condition, needs some cleaning.

Orange filters are used to highlight clouds and white buildings against clear sky, to eliminate haze, and to increase a picture contrast. Recommended for B/W film.