I've got one of the Harbor Freight Units like the one Lou has. I've used it mostly for re-inflating tires after coming off a rocky trail where I've deflated the tires to improve the ride of my truck. Its Ok, however it does warm up and the thermal protection will shut it down after 15 minutes or so. I turn it off and wait 10 minutes or so and it'll go again. It does the job. I only use it a few times a year and its 6 years old.