The Foramatron D10 apex locator from Parkell uses high- and low-frequency bands to pinpoint the apical constriction, even in contaminated canals.

When the tip of the instrument approaches the foramen, green lights track progress down the canal. As the instrument approaches the apical constriction, the lights switch to yellow, and a flashing red light indicates that the point for obturation has been reached. Orange indicates the apex has been passed.