*BRAND NEW* SimpliSafe Base Tower •Built-in 100 Decibel Siren •Voice Prompts guide you through installation. •Built-in Cellular and Wi-Fi: No phoneline needed. Twin cellular* and Wi-Fi connections run in parallel. So your home is protected even if your home phoneline is cut or Wi-Fi downed. •100 Sensor Capacity: You can purchase sensors, cameras, keypads, etc to add to the system. It will grow with you. •Backup Battery lasts up to 24 hours during a power outage. Base Station will recharge them once the power is restored to your home.