The fans switch off completely when the PWM signal is at 0 %. They support a "0 dB mode" in which the speed is throttled to standstill, which enables silent operation in idle mode. This means that they do not continue to run at a low speed when the PWM value is below around 5 % (or 0 %), but actually stop.
Due to different suppliers and delivery conditions, there may be price differences compared to other suppliers. We always try to set a price in line with the market, but this is not possible for all products.