Manufacturer designation:

691.H

Designation due to standards:

1000091 - GOST 8338-75
619/1 

Design:

The ball bearing consists of two rings (internal and external) and rolling elements (balls), connected with a cage - separator.

Features:

Made of high-carbon chrome bearing steel, characterized by high wear resistance and rolling fatigue strength.
Covered with a layer of stainless steel for working in aggressive environments and at high humidity.
Open type, without seals.