Air Filter Plus Pre-Filter Replaces Briggs & Stratton 491588, 491588S Air Filter; 491435, 491435S Pre-Filter. Quality Aftermarket Air Filter plus Pre-Filter Replaces Briggs & Stratton Air filter Part number 491588, 491588S Includes also replacement for Briggs pre-filter 491435, 491435S 4-1/2" Width, 5-1/4" Length, 3/4" Height