World Source Partners Sun Pottery Classic 2-Piece Ceramic Bird Bath in Light Blue Finish with a unique, strong locking device (not plastic). All of our ceramic and glazed bird baths are fired in gas kilns. They are SIGNIFICANTLY more environmentally friendly than the large "Dragon" wood ovens used by most of our competitors. The "Dragon" kilns burn a large amount of rubber wood with each firing, which is very bad for the environment and does not even provide cooking for the product. Our gas ovens ensure more uniform colors and a better quality product because the temperature is controllable; unlike that of wood-burning ovens. Frost resistant construction (down to -4 degrees f.)