Check the listing for details. Nitrous Outlet 4150 Billet Pressure Relief Plate. Condition: New. Listed at 219.99 USD. 4150 Flange 6061 Billet Aluminum Plate Pressure Relief Captured O-Ring Grove 1 Inch Spacer Why Our Plate?: Our Billet Pressure Relief Spacer plates are second to none in both quality and performance. Features. 6061 Billet aluminum plate, Spring loaded panels, Sealed with a captured grove o-ring, Works as 1 inch spacer as well. The relief plates can help save your intake in the event of a cough or backfire! The spring loaded panel will unseat allowing the pressure to escape instead of destroying your intake. Cheap insurance! Application. Fits any 4150 style flange, Carb, or EFI. *Note What sets our Relief plate apart from the others, The captured grove for the o-ring allows the o-ring to stay seated in the event of the panel opening unlike others blowing out!