that stuff is a quick fix I guess but I don't like the stop leak part of it. Just sends a crap ton of "gunk" to clog up any leaks..... problem is if you ever have it serviced at a shop when it's sucked down the reclaim machine it pretty much destroys it. From there, if they're smart they will charge you for a new machine if they find out you put stop leak in it. 4k extra bill not worth it.
That's my input on those refrigerant kits.... that and I don't understand why they sell them. it's still technically illegal to buy freon without a license.