They all come from the same supplier in China in including the lava tube so they are basically all the same no knock off, $28 to $32 if you buy 10 units. I agree with chopper, for the money they are a good Pv to get into VV vaping. In fact I have gotten to prefer it over the Provari because it is lighter and no error message. It just limits to 2.5 amps and continues vaping if you get too low on the ohms.