Thermaltake Mobile Fan II Adjustable Speed External USB Cooling Fan with One-touch Retractable USB power cable box for Notebook Laptop Desktop. A1888 Application for Notebook &amp; Desktop "Thermaltake" convenient solution with extremely "Mobile" concept inside Perfect accessory for NB &amp; PC Directly plug into USB port. Unnecessary additional power supply VR knob : Adjust fan speed manually One-touch retractable USB power cable box Slim USB power cable, only 0.6 mm in depth With "Tt" badge fan grille to avoid touching accidentally User-friendly installation