A bottle trap is a plumbing component that is used to prevent foul odors and gases from escaping from the drain and entering the living space. It is a U-shaped pipe that is typically made of PVC or ABS plastic and is installed under sinks, washbasins, or other plumbing fixtures that do not have a built-in trap. The bottle trap works by creating a water seal in the U-shaped pipe. When water flows through the trap, it fills the bottom of the U-shaped pipe, creating a barrier between the drain and the living space. This water seal prevents odors and gases from escaping through the drain and into the room. Bottle traps come in various sizes and shapes, including straight, curved, and angular designs. They may also have additional features, such as an adjustable height or a removable cover for easy cleaning.