Adapter AC 18 Volt 500mAh Extra long cable: The ultra-long cable provides you more convenience, You don't need to worry about the distance between the socket and the doorbell, It can be perfectly connected to your doorbell. Short Circuit and Overload Protection, High Efficiency and Low Energy Consumption Feature: Made With Fire Retardant Polycarbonate, combined with 3 layers of Protection - Protect Against Over- Current, Over- Voltage & Short-Circuit and ensures a safer charge. Contact: If you have any problems during use, contact us and we will try to solve your problem.