Great designed with 4 type of filling 1 or 2 cups and long and short, which means that even if you do not put a cup, you have 4 different volumes, more or maoins tight. Volume of conventional water but just a little below the threshold for who gets to 1/4 of the total volume, it flashes indicating you need to put water ... so useful volume 3/4. small gene, the tank ote by side so keep up the left side (no wall!). Easy to clean. Fine plastic. Excellent package and deadlines met.