Do not allow the small size of this vaporizer fool you, it works perfectly. I keep it by the side of my bed, and whenever my allergies start to flare just place a pad on it. The menthol just takes over, and calms down my seasonal allergies. I love that it does not require water as it makes it super easy to use. It does not take a lot of space and it is small enough to place away in a drawer when needed. The pads for it last about 7-8 hours but the menthol lingers in the air for a bit longer (which I enjoy).