Radium OEM Style Fuel Pulse Damper This OEM quality damper features a 3/8" NPT male thread with impregnated pipe thread paste. The opening and closing of the injectors creates pulses in the fuel rail, which can lead to unstable fuel pressure. This damper should be used (especially with high flow injectors) in order to achieve a safe and consistent rail pressure. The internal diaphragm will absorb oscillations and smooth fuel pressure. This correction can be measured throughout the RPM range and can often help an erratic surging idle. Specs Diaphragm OD 35mm (1.38")Overall Height 38mm (1.5")Wrench Hex Size 22mm Note For boosted applications, use these Radium Fuel Pulse Dampers