Moving water attracts birds. It also helps prevent the spread of West Nile virus by eliminating stagnant water in birdbaths. Water Wiggler's unique agitator action creates continuous ripples in the water, preventing mosquitoes from laying eggs. It's easy to install – just place and go! No wiring, no plumbing. It has a long battery life; it operates on two D-cell batteries (not included), and operates 24 hours a day. It may be used with heated birdbaths in winter to agitate the water and attract more birds. Dimensions: 5" H x 5" diameter. By Allied Precision Industries.