Damper flaps close when fan is turned off, keeping bugs inside. Extremely effective for outdoor and indoor use. Effectively lures and eliminates mosquitoes using TiO2 photo catalysis. Eliminates other flying insects including flies, wasps, moths, etc. 24W (watt) electric consumption is economical; just under $2.50/month. Easy-to-clean and maintain. DC (direct current) fan with ultra-long life and whisper quiet operation. Durable all-weather construction. Completely nontoxic; does not require any additional lures or attractants.