The device is nicely made, I like the functions. I used it to test the cold air for my air conditioning coming out of my heat pump mini-split indoor units. It seems to work fine. I like the black and yellow color of the device. I also used it when I bled the cooling system in my car to test the temp. of the heat coming out of the heat vents in the car, temp went up to 140 degrees which was perfect, which meant all the air was out of the coolant system. I used a 50/50 mix of 50% Prestone Antifreeze and 50% Deionized water. So therefore I found the device to be useful for home and mechanic's applications.