The RX4+ caliper is based on 25 years of experience in the design and manufacturing of hydraulic disc brakes, transferring the knowledge and skills acquired to the world of MTB brakes, cyclocross, and road.A precision CNC-machined monobloc design results in a stiffer caliper for unmatched feel and modulation.The RX4+ calipers come in different models:a Postmount caliper, Flat Mount Front Direct calipers, and Flat Mount Rear Direct calipers with the addition of a new Flat Mount caliper.Calipers designed to fit 140, 160, and 180 mm rotors.Slim and lightweight 4-piston design.The monobloc design creates a stiffer caliper that reduces lever feel and brake pad rub.Available in black, silver, red, blue, purple, and orange.CNC-machined from 2014 T6 aluminum.Calipers for mineral oil will have an M marking on the cap.Dot brake fluid calipers will have a D engraved on the cap.The RX4+ caliper is designed to work with the following Shimano and Campagnolo brake systems (mineral oil, Shimano recommended for Shimano applications, Campagnolo/Magura recommended for Campagnolo):Dura Ace Di2 R9170.Dura Ace R9120.Ultegra Di2 R8070.Ultegra R8020.105 R7020.Di2 R785.RS685.GRX RX810.GRX RX600.GRX RX400.GRX RX815 Di2.GRX RX817 Di2.RX4+ calipers compatible with Campagnolo:Super Record.Record.Campagnolo H11.RX4+ calipers are designed to work with the following brake systems (with DOT brake fluid):Sram Red eTap AXS.Sram Red.Sram Force eTap AXS.Sram Force.Sram Rival.Sram Apex.Sram S900.*Shimano and SRAM are registered trademarks and are not affiliated with Hope Technology