I bought this product for my caravan. Trailer tires require 65 psi. All commercial air compressors in retail stores such as gas stations do not exceed 35 psi. This product is easy to use and easily meets my 65psi requirements. Also, there are very few "tire shops" that test and supply air for free. It's also sometimes difficult to take a camper to a commercial site to get some air. Usually you block a few shop boxes. So when they work with you, they are not very happy about it. T