New! Add Moisture to the Air - No Electricity Needed Add moisture to dry winter air with these non-electric humidifiers. Add water to the bottom of the black ceramic vessel, and the white porous bowl on top absorbs the water and releases it into the air. Fill with water as needed. Set of 2, including one 3 ¾" Dia. x 3" H and one 4 ¾" Dia. X 4" H. Can be used together or separate."