The Shimano SM-MA90-F180P/P lightweight adapter allows the installation of Shimano Postmount caliper on forks and frames with Postmount 160 mm direct style in conjunction with 180 mm rotors. Product features - Shimano SM-MA90-F180P/P Fork-/Frame type: Postmount 160mm (PM6) Caliper type: Postmount Rotor diameter: 180mm Material Adapter: Aluminium Screws: Stainless steel Weight approx. 32g with screws