The Kidde Carbon Monoxide Detector is a 1-pack of plug-in wall detectors with a 9-volt battery backup. Each detector is designed for easy installation on walls or tabletops, using ionization technology to detect carbon monoxide. With a voltage of 120 volts, these detectors offer reliable protection for your home. The sleek white design and modern digital features make it a stylish and effective addition to any household. Trust the Kidde brand for quality and safety in your living space.