Conductivity of Water Tester Determine the conductivity of different liquids with this qualitative device which causes a bulb to glow when water conducts electricity. Because there's no shock hazard, due to a built-in fuse, it's safe for all ages. Includes plastic body with recessed connections and electrodes. Attaches to standard ring stand (not included). Operates on 110 V AC only. You will need a 15 watt bulb, not included. Qty :