Typical bicycle speedometers measure the time between each wheel revolution and give a readout on a small, handlebar-mounted digital display. The sensor is mounted on the bike at a fixed location, pulsing when the spoke-mounted magnet passes by. In this way, it is analogous to an electronic car speedometer using pulses from an ABS sensor, but with a much cruder time/distance resolution – typically one pulse/display update per revolution, or as seldom as once every 2–3 seconds at low speed with a wheel. However, this is rarely a critical problem, and the system provides frequent updates at higher road speeds where the information is of more importance. The low pulse frequency also has little impact on measurement accuracy, as these digital devices can be programmed by wheel size, or additionally by wheel or tire circumference in order to make distance measurements more accurate and precise than a typical motor vehicle gauge. However these devices carry some minor disadvantage in requiring power from batteries that must be replaced every so often in the receiver (and sensor, for wireless models), and, in wired models, the signal being carried by a thin cable that is much less robust than that used for brakes, gears, or cabled speedometers.