Dial or Digital?
1) Manual adjustment cleaner. The analogue adjustment ultrasonic carburettor cleaner has a simple knob / dial to set the cleaning time (0-20 minutes) and another knob for the temperature adjustment (20 - 80 degrees C). There is no LED display.
2) Digital adjustment cleaner. These models have a push button to set the cleaning time (0-99 minutes) and temperature (0 - 80 degrees C) with an LED display. The cleaning can be stopped mid-cycle and the temperature shows both the "target" temperature and actual water in the tank. In a workplace environment and working with hot water, there might be a health and safety implication that requires the tank temperature to be visible to prevent scalding to an employee.
3) Digital adjustment with degassing cleaners. As the above description but additionally these ultrasonic cleaners have the technical function of a degassing mode which, after a change a cleaning solution, quickly removes air from the liquid that in turn makes the cleaning process more effective. This is especially useful when cleaning a carburettor. Additionally, the ultrasonic cleaning power can be increased or reduced depending on the items being cleaned which means that delicate products can be cleaned gently. Generally, this function is more relevant on larger machines used commercially, where time equals money.