This is a BRAND NEW Rheem/Ruud/Weather King/Corsaire gas furnace burner. This unit works with MANY furnaces. It is 4 1/2" long 1 3/4" wide. The Part # is 75-24001-01 which replaces old part # 75-24267-01. The model that you have determines the number of burners you have (between 3 and 6 per furnace).
Burners are designed to mix the correct amount of air and gas for proper and clean combustion. The gas is regulated at the gas valve and many burners have air adjustments on them. Newer style burner called in-shot burners do not have air adjustments.