This battery case cannot be charged inside the machine, we will provide a dedicated charger The capacity of the 18650 version is 6000 mAh The capacity of the 21700 version is 9600 mAh We will try to send black, if you need other colors, please leave us a message This is a 3D printed battery case, it may not be resistant to high temperatures, please keep the temperature below 65 degrees Celsius. 3D printed products may not be as perfect as plastic products. If you are not satisfied with the items you received, please leave me a message Sincerely