This bundle includes 3x 120mm Lian Li UNI Fan SL-Infinity RGB fans with a controller (UF-SLIN120-3B) and 1x 120mm Lian Li UNI Fan SL-Infinity RGB fan without a controller (UF-SLIN120-1B) for expanding your system. The SL-Infinity fans feature a unique infinity mirror design to create stunning visual effects with 40 RGB LEDs per fan. They can be customized and synced together using the included controller for dazzling lighting displays. The 3-pack 120mm fans have dimensions of 120 x 122.1 x 25 mm and operate at 12V with airflow up to 61.3 CFM at 29dB noise level. The single 120mm fan is designed to interlock and sync lighting effects with the 3-pack for easier expansion, taking advantage of their daisy-chain connectivity. With their high airflow performance, infinity mirror design, and synchronized RGB lighting customization, this 4-pack bundle is perfect for building a uniquely stylish and well-ventilated PC system.