this kit does have a gauge on it, just not a fancy one. it displays pounds, and has a color coded sweep around the gauge, showing low, correct and high pressures. for the guy thats going to fill his truck once in a lifetime, it's a good deal. and, you can screw any of the cans onto it. on an r12 ride, i go to an a/c place and give them the refrigerant. the guys here will pull it out, and leave you with a vacuum in the system, so you can go home, add your oil, and add the refrigerant. not a bad deal, really.