The CanalPro Apex Locators are modern electronic length measurement devices, which provide a reliable method of confirming the working length. Electronic length measurement is often more precise than radiographic determination of working length and can be repeated at any time to verify canal length. Devices like the CanalPro Apex Locators determine the location of the apical construction with the help of electrical resistance. The large, user friendly panels of the CanalPro Apex Locators have a virtual apex function and also provides audio feedback for the dentist.