I didn't know something like this existed and was thrilled when I stumbled upon it. No more letting air in, pulling air out and reinserting it until you're close. ,,Do you understand. it inflates above the set value and then deflates until it reaches the set value. It's easy to set up and even easier to use. A tire on my wife's truck loses a little air every week and it really saves time. I did not receive a battery, but I did receive 8 AA batteries. Requires 7 AA batteries. I will buy it again and can recommend it.