Dynatron K555 77mm 2 Ball CPU Cooler Type: Fan & Heatsinks RPM: At Duty Cycle 0~20%: 1000 RPM At Duty Cycle 50%: 2500 RPM At Duty Cycle 100%: 4500 RPM Air Flow: At Duty Cycle 0~20%: 10.12 CFM At Duty Cycle 50%: 25.30 CFM At Duty Cycle 100%: 45.56 CFM Noise Level: At Duty Cycle 0~20%: 13.14 dBA At Duty Cycle 50%: 33.04 dBA At Duty Cycle 100%: 45.8 dBA Power Connector: 4 Pin PWM Heatsink Material: Copper Base & Aluminum Fins with Heatpipes embedded Compatibility: LGA 1156 Fan Dimensions: 77 x 77 x 20 mm