Best-electric Small Batteries or USB Mini Fan & Mini-air Conditioner(blue) Runs on 4xAA batteries or USB power. Adjustable analog speed control. Utilizes a 30db whisper-soft turbine system. Allows easy transformation from a hand held fan to a desk fan with a flat bottom Allows adjustment of the cool breeze of air with a rotatable turbine wheel Best for hot flashes, home and office use, camping, outdoor sports, watching the game, and more.