Aero Exhaust TR3.1 T304 3 inch inside diameter5 inch body 16 inch long resonator The TR3.1 resonator is our longest 3 inch resonator Made to fit in the tunnel of most cars and SUV's They help eliminate rasp caused by baffled or chambered mufflers and will produce a cleaner deep tone over a straight pipe Inside diameter: 3"Body length: 14"Outside diameter: 5"Overall length: 16"