JSC “ZASLON” is situated on the territory of the Ozoling Iron Foundry established in 1862. The Iron Foundry produced iron and copper castings, which supplied during construction of the Marine Cathedral in the town of Kronshtadt.

In the 1920’s 1930’s the Leningrad Textile Mechanical Engineering Plant was created there to manufacture machines for textile industry.

In October 1944 the Plant No.287 was created to the Order of the People's Commissariat of Aircraft Industry to manufacture radar and technical radio equipment for aviation. At that date, principal attention was focused on development and manufacturing of radio-electronic systems for aircrafts. Products manufactured by the plant were installed on aircrafts of different manufacturers: Tupolev, Sukhoi, Ilyushin, Mikoyan and Gurevich.

In 1966 the enterprise was renamed to the Leningrad Plant "Leninetz". From 1966 to 1993, the plant staff was rewarded with four government awards for development and manufacturing of advanced-technology radar facilities for aviation.

Later,  the Leningrad Plant "Leninetz" was renamed into the "Leninetz" Plant" State Enterprise as part of the Scientific Production and Foreign Economic "Leninetz" Concern. In 1992 the Concern was reorganized into the “Leninetz” Holding Company” Open Joint-stock Company. In 1993 the "Leninetz" Plant" State Enterprise was reorganized into the “Leninetz Plant” Open Joint-stock Company.

Over the years the Leninetz Plant has been a manufacturer of airborne radar systems for fighters, including MiG-31.

In 2001 the Scientific Research Centre “Leninetz Plant” Inc. was established on the basis of the “Leninetz Plant” OJSC. Мain activities of the Centre were development, manufacturing, modernization, and repair of avionics for different aircrafts, as well as development and production of climatic equipment.

In October 2014 the Scientific Research Centre “Leninetz Plant” Inc. was renamed into the Joint Stock Company “ZASLON”, Science and Technology Center. Main directions of activities of the enterprise are development, manufacturing and delivery of radio navigation facilities, avionics for different aircrafts, advanced radar facilities for navy ships, climatic equipment of different purpose.