LOMO OKS4-28-1 lens 2/28mm, T/2.4, OCT-19 mount for Konvas, Kinor, #770198
This high-quality lens was made in 1977 (#770198) at famous LOMO factory.
The lens is purposed for 35mm film movie cameras like Konvas, Kinor, Arri etc. Covered frame size is 16x22mm. Actual coverage is bit larger, but not enough to cover still image 35mm frame (24x36mm) - there are dark corners. Also, back focus is quite short, so it will not work with reflex cameras like Canon or Zenit. But will be fine for hybrid (mirrorless) cameras.
The lens has so called OCT-19 mount (for Konvas-2M and Kinor-35 cameras), but you may adapt it to other camera.
Mechanical condition is fine. Aperture control ring works well (T/2.3-16, no clicks). Focus ring is smooth (0.5m - infinity scale).
Optical condition is good. No fungus, no scratches. Some cleaning marks and many dots on inner surface (coating layer damage, most probably) - should not affect image quality.
Front cap and rear caps included.