An air purifier is a device which removes contaminants from the air.

and he will sit as a refiner and purifier of silver, and he will purify the sons of Levi, and refine them as gold and silver and they shall offer to Yahweh offerings in righteousness.

Then there s the GE MAC 400, a hand held electrocardiogram (ECG) device that costs 800 (the cheapest alternative costs more than 2,000), and the Tata Swachh, a 24 water purifier (ten times cheaper than its nearest competitor).