The Type-A Radium black and green high performance radiator caps are available in 3 pressure ratings and are designed for 32mm ID radiator necks only. Please confirm what style your radiator uses prior to ordering. Vehicle Fitment: - Subaru WRX & STi - Mitsubishi DSM/Evo - Nissan Models - MKIII Supra - Radium Coolant Expansion Tank (See more fitments below) Includes: (1) Cap Full Description: Radium high performance radiator caps are engineered to improve cooling efficiency. The radiator cap is an essential part of an upgraded cooling system and will help to safely maximize engine performance by controlling the coolant boiling point. Each OEM replacement radiator cap is manufactured from stamped stainless steel for durability and feature silicone sealing elements that are superior to natural rubber gaskets. Available in 3 pressure ratings: Part Number: Bar: PSI: Cap Finish: 18-0076-A11 1.1 16.0 Black 18-0076-A13 1.3 18.9 Black 18-0076-A15 (Pictured) 1.5 21.8 Black A higher radiator coolant pressure effectively raises the boiling temperature of the coolant, providing extra safety margin and preventing air pocket cavitation at the water pump. Radium radiator caps are designed for mini size (32mm ID) radiator necks only. Please confirm what style your radiator uses prior to ordering. Below are popular vehicles with their respective radiator cap style that is used from the OEM factory. There are many vehicles not listed below that will also use one of these radiator cap styles. Type-A Cap Vehicle Fitments: 1990-1993 Acura Integra 1991-2005 Acura NSX 1990-1993 Honda Accord 1988-1991 & 2016-up Honda Civic 1988-1991 Honda CRX 1992-2001 Honda Prelude 2003-2008 Infiniti G35 2008+ Infiniti G37 2014+ Infiniti Q50 2014+ Infiniti Q60 1992-2000 Lexus SC400 1990-1995 Mazda Cosmo 1990-2005 Mazda Miata 2006+ Mazda MX-5 1986-2002 Mazda RX-7 2004-2011 Mazda RX-8 1991-1999 Mitsubishi 3000GT 1990-1999 Mitsubishi Eclipse 2002+ Mitsubishi Lancer/EVO 1989-1998 Nissan 180SX 1989-1998 Nissan 200SX 1989-1998 Nissan 240SX 1990-1996 Nissan 300ZX 2003-2009 Nissan 350Z 2009+ Nissan 370Z 2005+ Nissan Frontier 2009+ Nissan GT-R 1989-2002 Nissan Silvia 1989-2002 Nissan Skyline 2005-2006 Saab 9-2X 1993+ Subaru Impreza 1990+ Subaru Legacy 2015+ Subaru WRX STi 2015+ Subaru WRX 1982-1995 Toyota Celica 1985-1995 Toyota MR2 1986-1992 Toyota Supra Radium Coolant Expansion Tank