Meters are available in many types, for use in countless applications. Pulse counters record the number of electric pulses the connected device emits, and find use in calculating energy or power consumed by the device. Tachometers measure the rotation speed of a disk or shaft, and display the revolutions per minute on either a calibrated analogue dial or on a digital display. Energy meters or power monitoring devices measure the quantum of electricity consumed. These meters can be calibrated to the desired unit. Electromechanical hour counters or meters monitor time. These meters are used in a host of devices, from UV lamps to car display panels, and from construction machines to car washers. Hour counters track the time elapsed and display it in hours and tenths of hours. These meters find use to track the running time of equipment, for maintenance purposes, and to start or stop a process. Multifunctional counters combine a range of functionality, such as pulse counting, tachometer, shift counter, timers, and section counters. These meters come in various options, such as scaling, input options and programmable presets. Each type of meter is made in many variants of range and form factor. Installation of meters may require accessories such as fastening plates, mounting frames, terminal coverings and panels. Some meters may also require transformers.