Oregon 35-022 Muffler Replacement for Briggs & Stratton 394180, 491413, 394170, 691874 220400, 220700, 251400, 252400, 251700 and 252700 series 5" L x 4-1/2" W x 3-1/2" thick 1-7/8" center to center Replaces Briggs & Stratton # 394180, 491413, 394170, 691874