The Nitrous Express .033 R/T single jet are manufactured on CNC equipment, and are guaranteed to be within .0005 of specified jet size. This jet has 35 percentage more flow through the same orifice than other jets. The horsepower jet was designed to be more than just a hole in a piece of brass. It has contoured inlet and multi-stepped outlet thus allowing turbulence free flow with no restrictions. Some claim brass jets are eroded by flowing gasoline and nitrous, thus making them inaccurate. The flow of gasoline and nitrous might cause wearing away of brass surface but it is a very slow process and will take a lot of years thus making it not much of a concern.