Polymer support insulators are designed for insulating and securing live parts in electrical apparatuses and distribution devices of power plants and substations for alternating current with voltages ranging from 1 to 220 kV and frequencies up to 100 Hz. They correspond to climatic designs U3 and UHL, placement categories 1 and 2 according to GOST 15150, and are intended for operation at ambient temperatures from -60 °C to +50 °C at altitudes not exceeding 1000 m above sea level.

The insulator's construction includes a fiberglass rod providing mechanical strength and a protective sheath made of silicone rubber, which shields the rod from atmospheric effects and increases the leakage path length. Metal end fittings ensure the connection of the insulator with live parts and support elements.

Insulators are classified by the following parameters:

• Design type: support rod (ОСК).
• Protective coating material: silicone rubber (К).
• Nominal voltage: from 1 to 220 kV.
• Mechanical breaking strength in bending: from 2.5 to 20 kN.
• Pollution level: from 1 to 4 according to PUE, 7th edition, ch. 1.9, STO 56947007-29.240.068-2011.
• Climatic design: U3 and UHL, placement categories 1 and 2.

Example of designation: ОСК 8-20-Б01-2 UHL 2 TU 3493-014-21639232-2008, where:

• ОСК — support rod insulator with a protective sheath made of silicone rubber.
• 8 — normalized breaking strength in bending in kN.
• 20 — nominal voltage in kV.
• Б01 — modification of structural height and flange connection dimensions.
• 2 — pollution level.
• UHL 2 — climatic design UHL, placement category 2.
• TU 3493-014-21639232-2008 — technical specifications.