The BR-M7120 is a 4-piston hydraulic disc brake caliper & is part of Shimano’s SLX series for Mountain bikes. The BR-M7120’s reduces disc break rotor wobbling noise & increase breaking power by 10% in comparison to the M8000 model allowing stable & versatile high-performance break control. This product uses Mineral oil brake fluid which is non-corrosive & less hazardous than conventional hydraulic brake fluid. In addition, it is very quick & easy to assemble.