I've been using an R12 replacement just like the one Fox Tool sells for years. I still have one vehicle that I installed it in over 10 years ago. I have NEVER had ANY problems with it. A lot of folks will tell you it's dangerous because its HC based. You are already riding around with 20 or so gallons of HIGHLY flammable gasoline, you aren't worried about that?? Heck I even used it in my house AC when I had to have a pipe replaced. That was about 5 years ago. No problems with it either. The problem is the LAW. The last I heard it was illegal for a BUSINESS to install the stuff. But YOU as an individual can buy it and do with it as you please. It CAN'T be any worse than that cancer causing 134 they have tried to pass off on us!! THAT stuff is BAD news!! When I replaced the R12 in my car the outlet temp actually went down a couple of degrees!! Great stuff ,,, in MY opinion!!! But hey,,, that's just ME!! Bruce Hevner