Chronometers are divided into two categories: LCD display and mechanical. They are a new type of instrument developed specifically for engineering machinery. The instrument adopts computer optimized design, has a reasonable structure, beautiful appearance, and can adapt to harsh working environments. It is widely used in vehicles for engineering machinery, construction, agriculture, material handling, as well as fixed equipment such as generators and compressors to record the working time of the engine. The instrument is flexible, convenient to install, anti magnetic, shockproof, and has good sealing performance, and can adapt to a wide voltage range; The wave crystal hour meter is controlled by a microprocessor, with clear display, high accuracy, and features such as power-off and memory functions.