Cellular repeaters are devices that enhance mobile phone signals in areas with weak reception. They work by capturing the existing cellular signal, amplifying it, and then rebroadcasting it to improve coverage. This is particularly useful in buildings, rural areas, or locations with obstacles that block signals. These devices consist of three main components: an external antenna that receives the signal, an amplifier that boosts the signal strength, and an internal antenna that distributes the enhanced signal. Cellular repeaters can support multiple users and devices, making them a practical solution for improving connectivity in various environments.