TRP Hylex RS Disc Brake Lever - Front Hydraulic 2-Piston Flat Mount BLKTRP Hylex RS Disc Brake and Lever Front Hydraulic 2 Piston Flat Mount Black. TRPs Hylex RS is a full hydraulic single speed disc brake system for road and CX. Designed for single speed aficionados who want simplicity without sacrificing braking performance. Flat Mount Only. Ergonomic and perfectly sized hoods create a natural extension from the riders hands to the bike It sports an integrated master cylinder within the low profile ergonomically shaped