Attention 18650 Battery is needed but NOT contained, you need to prepare by yourself. You'll need to buy yourself two 18650 lithium rechargeable batteries additionally. Most 3.7v 18650 batteries can work. Nice starter kit for someone who wants to get started learning and programming the Micro:Bit robot car. For children's education, you can program it for free using the web app called MakeCode This robot kit is very suitable as a gift for Kids. It will be a great thing if it is done together with parents. It not only helps develop children's programming potential and improve their hands-on ability, but also promotes the relationship between parents and children. If users have the theoretical basis of electronic programming, they will get started with this kit more quickly. Follow the black line This kit contains a line tracking sensor which will make the robot follow the black line intelligently. Avoiding the obstacles Comes with an ultrasonic sensor, so you can code the robot to avoid the obstacles when run. Also provides several ultrasonic stickers for the robot so could catch others' eyes easily. Ultrasonic following Provides example sketches to program your own robot to follow the front objects. IR remote Includes an IR remote controller for you to navigate the robot car run in different directions. Come with Free mobile app to control the car remotely via Bluetooth pair. Android device: Android phone or tablet. (Search keyes Bit Car on Google Play and install App.) Run iOS: (Search keyes Bit Car on App S tore and install App.)