I was really impressed: 4 tires 225/45 R17 from 2.1 to 2.5 bar in 35 sec for each tire and the battery didn't lose a single bar.

After 2.5 months of staying in the trunk, I used it and inflated completely empty Jeep tire sized 245 with 35 psi in about 10 minutes. Even though it was 1 in the morning, it didn't make a loud noise to bother! I have another bulky one (battery starter and compressor) that sounds a lot.. It is convenient, effective, and lightweight. I chose the category for Jeep, aimed for 35 psi, easily attached the air hose to the tire, and everything happened automatically and easily. The 2 amp battery had 4 bars just like before! The only reservation I have, as with all rechargeable batteries, is the durability of the battery. Time will tell. (Of course, charging every quarter..)