The regulator does not have a part number on it but it is very similar to the link in the prevous post.
As for notes on using it...
I still pulsed the charger and simply used the regulator to limit the maximum pressure.
I do not think the cheap hand held CO2 charger can really hold up to the sustained stress of the cartidge pressure, which gets up to 850 PSI.
NEVER fully close the regulator, pulsing the charger with no place for the gas to go is where the bad things happen (850PSI through a pin hole dissipates to low pressure quickly, but you need to give the gas some place to dissapate pressure to... like a keg)
I never dialed in the regulator to a specific "12 or 13 PSI", I just dialed it back so that the keg does not get too much pressure, and left it. (again, never fully closed the regulator... I started Hi and worked lower so that the gas always had someplace to go. I might be over cautious... but that was my thinking on dialing it in)
The Williams ones, reporteldy will let you dial in your PSI and you can leave it "on" all the time. It is a better quality setup for sure, while mine is a step up from spit and bailing wire and duct tape. :-)
If you are going to use it 5 or 10 times a year, I would say spend the money. If you are like me, and only bring a keg or two to the christmas party once a year (the rest of the parties seem to be at my house... the curse of having lots of good beer on tap during the holidays), then I found this to be an acceptabe $15 solution to a minor problem.
Enjoy!