air cooling fan 1.size:4inch 2.material:ABS&PP 3.fan parameters:5v,2.1W,2300RPM 5.Features:super quiet, 25000h ... wind, super quiet.2.5V USB(cable length:1.2m) power supply, plastic shell, special mesh enclosure design, all has been ... brushless technique, lower running voltage and current, power just 2.1W, energy saving.4.Fan's life can be 25000~30000 hours ...