This washer serves as the shaft locating ring in an axial cylindrical roller bearing arrangement of the 811 series, used together with K811 and GS components to form a single-direction axial cylindrical roller bearing set. Bore diameter is 30.0 mm and net mass is 22.5 g. As a flat locating washer, it provides the running surface against which the rollers and cage assembly operate on the shaft side. Being part of a single-direction axial cylindrical roller bearing, this washer transmits axial load in one direction only and must be paired with the corresponding K811 roller and cage assembly and GS housing washer to form a complete bearing. The flat, hardened contact face supports pure axial loading and requires adequate lubrication at the roller contact points; correct alignment with the mating GS washer and shaft shoulder is required to maintain the intended load path.