Cool gas
Bought this for an Audi A4 recharge. You _must_ also own, borrow or buy the short hose with pressure gauge which will connect the canister to the air conditioning system. First it has a piercing needle to allow the canister contents to be moved to the car's AC, second you really want to know that the AC system pressures are Ok.
There are a few videos on YouTube for further advice. I used a leak sealer (green tin) which I already had plus one blue can. If your AC system still has reasonable pressure you probably don't need the green leak sealant. Get the canister slightly warm (do not exceed 50C, I left mine in the airing cupboard overnight) and perform the recharge on a cool day when the ambient temperature is below 25C.
If you only need a top-up maybe this is not the right product for you. Screwing the needle in to shut off the gas transfer is the only means of saving a part canister, and I am not sure how long a partial can would remain safely stored. That aside, it works fine.
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