The Pagid Disc Brake Pad Wear Sensor Set - 355251911 is a set of sensors designed to detect when the brake pads on a vehicle are worn down and need to be replaced. These sensors are specifically designed for use with Pagid disc brake pads and are compatible with a variety of vehicle makes and models. The set includes two sensors, one for the left side and one for the right side, and they are easy to install and replace. The sensors are essential for maintaining safe braking performance and preventing damage to the brake system.