The NEW SimpliSafe Entry Door/Window Sensor (ES1000) is a wireless unit designed for indoor use. It comes in a lot of 4, each powered by a battery with the model ES1000. This sensor is compatible with SimpliSafe systems and features a sleek white color, making it a discreet and effective addition to your home surveillance setup. With easy connectivity and reliable performance, this sensor is an essential component for enhancing your smart home security system.