The Solinst Model 101 P2 Probe Water Level Meter is designed for measuring the depth of water in wells, boreholes, and standpipes, the Solinst Model 101 P2 Probe Water Level Meter is the most accurate and reliable meter. It is sturdy, easy-to-repair and read to 1/100 ft. or to each millimeter. The Model 101 Water Level Meter uses a choice of probe designs, attached to a permanently marked polyethylene well tape, fitted on a well-balanced reel. It is powered by a standard 9 volt battery housed in an easy-access battery drawer. The conductors embedded within the well tape each have seven strands of stainless steel for strength and flexibility. The probe incorporates an insulating gap between electrodes. When contact is made with water, the circuit is completed, activating a loud buzzer and a light. The water level is then determined by taking a reading directly from the tape at the top of the well casing or borehole.The high quality polyethylene well tape reels smoothly, remains flexible and hangs straight in the well, irrespective of temperature. Permanent markings at each millimeter or 1/100 ft. allow accurate readings, traceable to national standards. Stranded stainless steel conductors resist corrosion, provide strength and are non-stretch. They make the tape very easy to repair and splice. The dog-bone design reduces adherence to wet surfaces. Markings are permanently impregnated onto one side of the well tape in your choice of scale. Standard reels are ergonomically designed for good balance and ease of use, with a stand-alone design, convenient carrying handle and an excellent brake. They are robust and smooth running. The battery is housed in a convenient battery drawer and each reel has a probe holder and brake. The reels are equipped with an on/off sensitivity switch, light, buzzer, and a battery test button.