Monolithic Inflator F15 is ideal for the small domes because it is almost self regulating. The maximum pressure is about three inches of water column. By the time you figure in the air leaks around the door of the airlock and a small escape of air in other places you wind up with the two inches.
Sometimes you have to spray sealer around the base when you are applying the Urethane in order for the fan to inflate to the two inches. These are really good fans to use if you are only building one or two domes or you are staying strictly with the small domes (20 to 30 foot). If you are going to build the fifty foot dome, you certainly want two of these and one run off a generator at least in the critical times.