To set, just choose the heat temp you want by pushing the button. It scrolls through your choices and once you come to the temp, just stop pushing. Shows current and set temps in red.

Straight forward heater and controller. Easy to see, even under bright lights. Installed it a little bit ago and so far so good.

Two suction cups to keep the heater in place. Holding accurate temp and staying put horizontally on the back wall of the tank. Holds temp in aquarium nicely.

It’s very easy to use and keeps the water at the chosen temp. I also have a temp strip on the front of the tank to reassure the heater is distributing an even temperature throughout the tank. Works perfect on my 20 gallon aquarium.

Shows an error message on startup. And can not adjust temperature. Returned for a refund, not a replacement.