Necessary !!! , Operates in 5 volt pulse and more air than 5 ventilos 12 volts !!! a silence that worth gold! The blades are grainy! normal golf balls are not smooth! to better penetrate the air, granulositées blades make all the difference between classical and ventilos noctua ... 7 blades only! but with an inclination of 45 °: no noise but what noctua wind !!! it liberates max. I can not imagine if it was powered by 12 volts !!!
ps) tastes and colors do not discuss but there! hard hard dull brown and beige! ...
