This Mini DC Rechargeable Fan Circuit Board is an all-in-one charging and speed regulator module designed for portable, handheld fans [Image 1.3.1, Image 1.3.2]. Powered by a standard 3.7V 18650 lithium battery, it features an integrated Micro USB port for easy 5V recharging and dual status LEDs to indicate charging activity [Image 1.3.1, Image 1.3.13]. The onboard tactile switch allows users to seamlessly cycle through 3 levels of fan speed control, making it the perfect drop-in replacement motherboard for repairing or building custom portable cooling gadgets