A capacitive measurement device for indicating when two surfaces moving relative to each other are spaced less than a predetermined distance apart. The device comprises a probe having an elongated conductor, an insulating core, a conducting inner guard, an insulating interlayer, and a conducting sheath. A portion of the conductor, insulating core and conducting inner guard form a probe tip which extends beyond the insulating interlayer and conducting sheath by a predetermined offset. The probe is configured to extend from a first surface by a predetermined distance and to generate a signal when the tip is contacted by a second surface.