Instructions were easy to follow. When I received it', it was already charged, so i could check all four of my tires, which were all low . Was getting 22 miles to a gallon of gas , that has went up to 25 ! With the price of gas it will pay for itself before long . Good investment for the money ! Had to then Recharge it . took about an hour and a half, I can live with that, plus it gives me a lot of peace of mind just having it in the car ! Thanks I'm glad I ran a crossed this Item !