The braking process in hydraulic brakes that are ofetn used in scooters, mopeds, mopeds, shift mopeds and maxi scooters is triggered by the brake lever and brake pump, also called brake cylinder. This is where the hydraulic pressure is transmitted via the brake line. With most models, lever and cylinder form a unit, so you don't have to buy the lever separately ... A no longer properly functioning brake pump must be replaced immediately to ensure safe braking. We have many brake pumps in standard quality, e.g. for Grimeca or Brembo systems, which replace the original part 1:1. For tuned racing bikes you should consider getting a high-end model with optimized pressure point and better dosing, we recommend Stage6 or Motorkit.