Technically you can use any T-fitting, including one like the MB Sturgis Sturgi-Stay T-Fitting for POL Valve # 103537-MBS before or after your propane regulator. The correct placement and T-fitting is going to depend on what you are trying to hook up.
More often than not you are going to want your T-fitting before the regulator. You do not want your propane to be double regulated because it is going to cause you to not have enough gas pressure for your appliances to work properly. Basically... view full answer...