It is sometimes problematic to detect an unpleasant sound in the underhood of a car. Anything can make noise: both an unadjusted valve in the engine and an alternator bearing. In order not to drink valeriana from the thought of an approaching engine overhaul, it is better to use a stethoscope. The device will help to calculate exactly what knocks in your car. The device has a length of 34 cm. The stethoscope is made of metal and plastic.