17-3/4" x 17-3/4" Egg Incubator With Still Air, Made Of Durable Styrofoam To Help Retain Warmth & Keep A Constant Temperature, Incubators Feature Two 4" x 8" Viewing Windows, Ideal For Educational Purposes With Solid State Thermostat Control, Thermometer & Moisture Rings, Wire Grill Safely Supports Eggs During Hatch Period.