I was very skeptical about how well this device would work. It was one of the cheapest of its kind but it was the only one available with slow shipping due to the virus so I took a chance. I couldn't be happier so far. Not only does it snap onto the valve stem and seal well, the gauge seems pretty accurate too. When I checked my mechanical pressure gauge, they were the same every time. The physical effort required to inflate a tire with a simple trigger is minimal. A HUGE improvement over holding an air chuck on the valve stem and a huge time saver! While I consider this product 5 stars, it should be noted that I received a $5 refund for this review, as probably did many others.