Air Filter 5.23" x4.51" x0.85", A & I Products, Mfr#: A-B1SB2838

Air Filter, Dim A (1): 5-1/4" L, Dim B (2): 4-1/2" W, Dim C (3): 3/4" H, Replaces: Briggs & Stratton 399959, 491588