Intended Dimensions: 45 mm inner / 57 mm outer (indicated in your spec) — used in front fork assemblies for certain CR / RM models.
Type: Dust seals (sometimes called wipers) — they prevent dirt, debris, and water from entering the fork seal area.
Application / Fitment: For CR125, CR250, CR500, RM125, RM250 fork legs using that 45×57 size.
Construction & Features:
• Made from a durable elastomer/rubber compound that resists abrasion
• Designed to slide smoothly over the inner fork tube without too much drag
• Often sold in pairs (one for each fork leg)
Usage: Replace when seals get nicked, hardened, leak, or let debris into the fork internals.