The first model I bought was the A2 model. The pump worked great aside from the fact that the LED flash never went out completely so the internal battery was constantly draining. I contacted CS and Steve from CYCPLUS got back to me within 24 hours and upgraded me to the A7 model. A week later came a new model. I loaded it up and purposely deflated my cruiser tires a few pounds, set the pressure to 38 pounds for the front, and then 40 pounds. For the rear tire and it was turned off immediately. Both times when I disconnected the air hose from the tube stem I fully expected a small air leak as my bike has tight spokes so adding air is not very easy. Not a single sound and no escaping air. The pump showed 40 pounds. And immediately jumped to 0.00 lbs with no air loss. I really love this shop. It fits in my saddlebag and takes up almost no space or adds noticeable weight. I can absolutely recommend this product. I can't wait to try the A8. get it!