Briggs & Stratton After Market Flat Air cartridge filter OEM #'s 491588S , 491588 , 399959 , 4101 , 4915 , 5043 , 5043B , 5043D , 5043H , 5043K. Craftsman 3364 , 33644 & Stens 102-549 (4 Pack) Brand-new, aftermarket Briggs & Stratton air filter, Fits part# 491588S Fits many lawn mowers and Briggs engine models. Compatible with 625-1575 Series & 625-725 Series 3.5-6.5 Gross HP Engines. Regularly replaced filters improve engine performance and engine life. Incredibly easy to change. Changing air filters helps fix engine surging and lack of power. Includes (4) filter cartridge