The Shark NeverChange Air Purifier Max uses the longest-lasting filter of all Shark air purifiers. When powered at Max fan speed for 12 hours per day in a 300 sq. ft. room, Shark says the filter ...

You don’t use it like you would your typical air freshener spray. With your car running, the doors closed and the AC on, set off one can inside your car and wait 10 to 15 minutes.