Making its way onto the new Shimano Deore 12-speed group is the updated Deore BR-M6120 Disc Brake caliper. At the heart of the new M6120 is the high powered four-piston system that offers high stopping power and quick retraction after letting off the levers for excellent modulation and a small and large piston engagement sequence. Smaller pistons engage with the incoming rotor, followed up with larger pistons to handle the larger stopping forces. This reduces rotor wobbling under load and also reduces noise and chatter to help you enjoy the ride instead of fretting over concerning bike noise.The M6120 keeps your lines and your garage cleaner as well with One Way Bleeding tech that, you got it, has one way bleeding to prevent air bubbles from being trapped in your lines, which improves braking feel and safety. Add a funnel tool for easy cleanup too. You'll also be pleased to see that Shimano's high-performance ICE Tech is onboard to keep temps under control during extended periods of braking.