Top off your radiator with Billet Specialties dome style radiator cap. Featuring a 6061-T6 billet aluminum top with knurled grip sides in your choice of 7 lb. or 16 lb. caps. Please note: 7 lb. radiator caps are designed for use on original radiators and 16 lb. caps are for use on new replacement radiators like Walker, PRC, BeCool, Afco, etc. You will want to use the highest lb. radiator cap that you can as for each lb. of pressure in your radiator, it will increase the boiling point of your antifreeze by 2 degrees.