A flat-plane crank is a type of crankshaft used in internal combustion engines that has a 180-degree angle between crank throws. It is used in V-configuration engines, generally with eight cylinders, and is commonly associated with European sports cars such as Ferrari and Lotus V8 engines. Inline-four cylinder engines almost all use flat-plane cranks, and thus are not usually identified as such. The flat-plane crankshaft is a design that is no longer used in most mass production V engines as it is more prone to vibration and is inherently much louder than a cross-plane crankshaft. However, due to its simpler construction requiring less counterweight, it is inherently lighter with a higher rev limit, making it useful in sports and racing cars. The flat-plane crankshaft is also known for its distinctive high-rpm whine.