Upgraded Car fan with Durable hooks This portable car fan comes with durable hooks. This fits securely into the headrest of the car and fastens the fan to the rear seat. You can easily install it manually without any other tools. Please read the user manual for installation before use. Various power sources Car fans can be powered via USB ports, such as car chargers and mobile power sources (including 59 "USB cable). The fan can also be powered by a rechargeable 18650 lithium battery (containing 1*2200mah). Depending on speed, a full four hour battery will work for two to eight hours. (The battery can be replaced with a higher capacity 18650 flat-top battery). The wind speed of the fourth gear can change from soft wind to strong wind. The strongest wind speed reached 4000rpm, and the maximum wind volume reached 4.5m/S, much stronger than its small wind volume. 100% pure copper brushless motor, unique air duct design, noise reduction of nearly 20dB. Work quietly and do not disturb resting passengers. 360-degree rotatable, compact, 360-degree horizontal and vertical rotations keep you cool from all angles.