Basic technology, yet ingenious application, this automatic-refill version of the Allied Precision Kozy bird bath line is made of durable materials to resist corrosion and scale build-up. Water supply line is hidden in the pedestal. Simple set-up. Automatically refills after bird bath is emptied for cleaning. Air pressure forces water from the reservoir to rise to the same height in the birdbath. The Kozy Fill runs off gravity, so no electricity is needed. 3 year material and workmanship warranty. Will not crack in winter or in freezing temperatures.