The premium plus all season high powered roof mount (1500 cfm)is an electric powered attic vent. It uses a thermostat to fight heat and a humidistat to prevent moisture build up inside the attic. The thermostat adjusts from 60 to 120 degrees and runs fan in summer. The humidistat adjusts from 20% to 90% and runs fan in winter. It ventilates an area up to 2100 square feet and needs 720 square inches of net free intake area. Other features: 25" diameter metal dome, 4.3 amp motor, 6 bladed fan blade, 14-1/2" diameter opening. Color is gray. There is a 10 year limited parts warranty and a 5 year limited labor warranty.