I purchased this model 4 years ago. It has 4 transducers, adjustable heater, and holds 2.5 gallons.
https://www.ebay.com/itm/10L-Liter-S...cAAOSwfz9gGKb3
It has worked well and I've had no issues. I use it for cleaning transmission bolts and other small transmission parts while the larger parts are going around in my jet spray cabinet. I use the same Zep chemical in the ultrasonic cleaner that I use in the large jet spray cabinet. I have used this to clean carbs as well. What I have found is using my soda blast cabinet works well to clean a carb prior to running through the ultrasonic cleaner. As mentioned by someone else, once the cycle is complete, remove the items from the cleaner. If you don't, the suspended particles will fall and attach themselves back onto your parts.