Hope RX4+ Brake Caliper Complete - FM Std - DOTHope RX4+ Brake Caliper Complete FM Std DOT RX4+ Flatmount DOT Caliper Designed to fit on Flatmount Front and Rear mounts with an adapter to allow the use of 180 160mm front and 160 140mm rear rotors dependent upon mount type. For use with DOT Oil systems only. Compatible with: Sram Red eTap AXS Sram Red Sram Force eTap AXS Sram Force Sram Rival Sram Apex Sram S900 Features: Front Rear Flatmount caliper Drop bar hydraulic calipers Slimline 4 piston