Be confident in your purchase we're an Authorized AutoAqua Dealer. How cool is that?!?!? Specs: Charging : USB 5V Charging Time : 120 minutes Size : 2.77 x 2.77 x 2.34 inch (70.5 x 70.5 x 59.5 mm) Holder Size : 27 mm in Diameter The AutoAqua Smart Stir Aquarium Water Mixer is a small but clever labor-saving gadget to help you mix water test reagent with ease. Its strong motor and tiny magnetic stirring bar allow you to mix liquids completely and effortlessly in a moment. Just drop the magnetic stirring bar in the container, put it on the stir base and press the power button, Smart Stir will do the annoying labor for you especially when you have to do several tests. It will stop automatically after five minutes in case you forget to turn it off.