These nice fans cannot be fully pwm controlled, they have a minimum low speed. They produce a lot or airflow at full speed so cooling down quickly.
I give a star because the received product is used and this information does not appear on the site. I do not agree in any way with the lie and deception of the buyer. Sellers can sell such used products but must inform buyers correctly. I will never buy from this store again. It is the first time I give a store a star for lack of fairness. I will not open a dispute to recover the money, but I advise those who buy to be very careful about what they give the money.