Review on NOYITO USB Fan Speed Controller with Stepless Speed Regulation & Switch, 4-12V to 2.5-8V, 5W, Pack of 2 by Paul Dye

This product is great for my use case; which controls the speed of the Scythe case fan that I use to cool my PC case. At full speed and at the lowest speed it works perfectly; but at any speed between them there is a high-pitched electrical screech of its own. what can be annoying. Fortunately, the fan is almost as quiet at full speed as it is at its lowest; So I don't mind going full throttle.