Heated Rock Birdbath De-Icer keeps your birdbath ice-free all winter long, disguised as a decorative rock. This thermostatically-controlled, cast aluminum de-icer turns on automatically when water temperature falls below 35°F. Keeps water ice-free even in sub-zero temperatures. Uses just 75 watts and operates for just pennies a day. Requires a fully-grounded extension cord. Comes in tan, but surface is paintable to match any birdbath tone. Safe in all birdbaths. 3-year manufacturer's warranty. 5-1/8" x 5-1/8" x 3/4" thick.