Well I think that's the tank style....3.5ml, clear with black hard plastic ends. Anyway, 2 problems. 1- while inserting the cartos they are sharp edged and shave tiny pieces of the plastic off...which float around in the tank. 2-I have dumped juice out 3 times while trying to top off the tank. I try to gently pull the cart down but it pulled all the way out! Is there a tank that is easier to top off....maybe a screw in carto? How's the Vivi for refilling? Thanks!