The Shimano SM-MA-F180P/P2 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-MA-F180P/P2 Fork-/Frame type: Postmount 160mm (PM6) Caliper type: Postmount Rotor diameter: 180mm Material Adapter: Aluminium Screws: Steel