I had a flat the other week and used the repair kit successfully. The car engine must be on, connect to the 12volt outlet and set unit to "repair" and run for 10 full minutes. Then switch to "air" inflation and turn off when about 35 psi. The tire drove just fine for a few days until I got a replacement Michelin green tire. In another post I mentioned the "low air pressure" indicator is now always lit. When I buy 4 new tires the calibration will reset and the indicator will operate correctly. But anyway, the repair kit worked fine and I actually use the unit to inflate whenever necessary. I was wondering about how many uses it gives before needing a new can of sealant. Useful to read it may only be one, but it might be good for another, who knows. I used the code reader with my iPhone on the unit as my manual was not in the car when I got the flat. It links to a short video on how to use it. I drove too long before pulling over, and the outside of the tire indicated internal damage, so I replaced it instead of trying to repair the tire. Better safe than sorry!