This tap has a tapered thread and should only be used with the 2" cap barrels, that have an inbuilt threaded insert. Please note that no nut is supplied with this tap. TIP: The best "off" position for this tap is not where the lever is pushed fully back. If you look at the tap from above when the lever is pushed fully back it will be at the 2 o'clock position. If you bring the lever forward slightly to the 3 o'clock position this will give you the best seal.