Vibrant Performance standard bottle style resonators are round bodied, densely packed with our premium multi - layered sound absorption materials, and manufactured from 304 stainless steel for optimum durability and corrosion resistance. Vibrant Performance standard bottle style resonators have a sleek design that is optimal for easy installation and work to maximize the reduction of exhaust db levels. They are available in 12 18 overall lengths and inlet I.D. diameters ranging from 2.25 to 4.