Arnold Briggs & Stratton Gas Cap for Quantum Engines - 1-3/4-Inch Replacement vented gas cap Fits Briggs & Stratton Quantum, Max and Europa Series engines, 2011 and prior Replaces Briggs & Stratton model 397974 Replacement vented gas cap Fits Briggs & Stratton Quantum, Max and Europa Series engines, 2011 and prior Replaces Briggs & Stratton model 397974