YOU ARE BUYING 1 SERVER GRADE 12V 2.5Amp FAN 285 CFM Ultra High Airflow Fan used in Mining Rigs, Servers, Bitcoin Servers, Gaming Computers, Pro Amplifier Cooling, etc. DON'T GET FOOLED BY HIGH RPM SPECS, IT'S THE CFM SPECIFICATION THAT TELLS YOU HOW MUCH AIR THE FAN WILL MOVE!!! Can be used as a regular 2-wire 12V fan by connecting only the Black (-) and Yellow (+) wires to 12VDC @ 2.5 Amps Regulated Power Supply (Blue Wire: do NOT connect!) then the fan will work at its highest airflow rate of 285 CFM. NOT designed to be powered by a Battery and/or Charger!!!Dimensions: 4.72" x 4.72" x 1.5" (120mm x 120mm x 38mm)Soft Start CircuitNominal Voltage: 12V DCOperating Voltage Range: 8VDC - 13.5VDCCurrent: 2.5 Amps *(For multiple fans, you need 2.5A per fan, otherwise they won't reach top speed! For example: If you connect 4 fans together, you need a 12V @ 10A (UL Approved) power supply to reach full Speed)RPM: 1,500 to 5,200 RPMAirflow: 285 CFM @ Max speedNoise Level: 72 dB @ Max speedBearing: Ball bearings (Can be installed vertically or horizontally!)7" long leads terminated with a 4 position Molex male plug (DO NOT CONNECT TO A MOLEX PLUG WITHOUT FIRST CHECKING THAT THE WIRING CONFIGURATION MATCHES: BLACK:NEGATIVE, YELLOW:POSITIVE, BLUE:PWM. Pins can be repositioned in the plug to match your wiring configuration) 3 wires - Black: (12V- Negative), Yellow: (12V+ Positive), Blue: (Optional PWM controller input. (if PWM controller is not used, then DO NOT connect blue wire to avoid catastrophic failure!!!) PWM Input: 25 to 30kHz @ <0.8V Low 3-10V HighThis fan does NOT have a tachometer output signalPower: 30 Watt7 blade plastic impellerBrand: TKFANCE and RoHS CertifiedWeight: 10.7 oz (303 g)