i basically have the same machine...built by the original manufacturer that supplied them to snap on ( White?)...it is a recycler, not a charging station...what it will do is remove the freon from your system and store it in the bottle below...then when its time to recharge you can pull it out of that bottle...but it doesnt pump it in under pressure, its just like pulling it out of a little can or big bottle...but if you only have the charge from your car in the bottle on the recycler, its would be under such low pressure that it would be very hard for the compressor on your car to suck it back out...and i wouldn't trust the contents of whatever's currently in the bottle cause it could be contaminated or be a cocktail of "r-12 substitutes" like propane or even 134 from improperly done conversions...the machine should be marked that its designed for r-12 and have the corresponding fittings...by the time you get a new tank and change the dessicant filter( if you can even get one) it would be easier to just buy new r-12...we were required by NY state law to have one of those in our shop but basically it sat in the corner gathering dust so if an inspector ever came in you could point at it...no idea how we were supposed to properly dispose of a full cylinder of bad freon...