Allied Precision Water Wiggler without sensor agitates water to eliminate stagnant water in bird bathsand prevents spread of West Nile virus. The unique agitator action creates continuous ripples in the water, preventing mosquitos from laying eggs. Attracts wild birds all year around. Easily installed. Place and go! No wiring, no plumbing. The water wiggler agitator has a long battery life: operates 24/7 on two D-cell batteries (not included). It may be used with heated birdbaths in winter to agitate the water and attract more birds.