The 18650C HAT is a rechargeable battery base designed specifically for M5StickKc, with a built-in 18650 large capacity rechargeable lithium battery that can provide devices with longer battery life. The base adopts the plug-in structure design of the HAT series and can maintain reliable connection with for M5StickC when in use. The bottom is equipped with a USB charging interface, which can conveniently and quickly charge the battery. The USB interface of the base is only used as a charging interface and does not have serial communication function. The back of the base provides various types of mounting holes, allowing users to easily install it on various surfaces with a battery capacity of 2000mAh. Battery replaceable. Note: for M5StickC produced after October 2019 has added a fixed hole design on the back. If your for M5StickC is an old device (without fixed holes), it cannot be fixed to 18650CHAT with screws, but this does not affect the functional use of the module. Color: White Material: Plastic Package Contents: 1 x Battery Base Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.