The Shimano SM-MA-F203P/S adapter allows the installation of Shimano Postmount caliper on forks with IS2000-Standard 160 mm direct style in conjunction with 203 mm rotors.
Product features - Shimano SM-MA-F203P/S

Fork type: IS2000-Standard (160mm)
Caliper type: Postmount
Rotor diameter: 203mm

Material

Adapter: Aluminium
Screws: Steel