This machine seems to be a good bargain for the price. Like most ultrasonic units (I own a couple of other brands in larger sizes), the claimed or rated volume is rounding the capacity of the cleaning tank, which I measured at 3.4 Liters, and the directions tell you to fill 3/4 of the way, though they don't specify if that is 3/4 of capacity or 3/4 of depth on a ruler. I filled mine to the top edge of the step in the tank wall, at which point it is closer to 2 liters, and that's what I've run it with. I want to allow that liquid will be displaced by the object I am cleaning. In using 2 liters at 40 KHz I can see streamers of cavitation bubbles come off the transducers, which is more power than some more expensive machines provide, and it cleans effectively.The only reasons I am giving four stars instead of five are that the temperature sensor is not very precise, putting the water at 43° when I set it to 40°C (confirmed by a Fluke Model 52 thermocouple thermometer with calibrated K thermocouple and an IR thermometer and a digital meat thermometer), though this is minor and if you need a more precise temperature, you can use a thermometer to determine the setting correction to make. The second issue is a common one with most imported technical goods, and that is they need a native English speaker with some technical understanding to go over their manual and the labels on the machine. I would have done it for them for free in a few minutes, but there was no factory address to send to.