The Bosch Knock Sensor - 0261231096 is a sensor designed to detect engine knock or detonation in a vehicle's engine. It is a vital component in the engine management system and helps to prevent engine damage and improve performance. The sensor works by detecting vibrations in the engine caused by knocking and sends a signal to the engine control unit, which then adjusts the engine's timing to prevent knock. This sensor is compatible with a wide range of vehicle makes and models and is a reliable and durable choice for engine knock detection.