Control 4 Fans Simultaneously 4 channels stepless fan speed control, specially designed for PC enthusiasts. Cool Appearance with Blue LED With blue LED surround each knob to make your computer case with side window more awesome. Reduce Noise Reduce noise and maintain proper heat levels to keep all the parts of your computer running with high performance. 3.5’ Drive Bay Compatibility Designed to fit in a computer case with a 3.5’ drive bay, easier to install. Manual Control Manually adjust from full speed to low speed, the slower the fan, the quieter it will be.