Some brands of lawn mower gas caps are Craftsman, Briggs & Straton and Troy Bilt. All three brands manufacture gas caps specific to the brand's four-cycle lawn mower options.
Briggs & Straton gas caps include those with and without an attached fuel gauge. The gas caps include models that feature locking ears and quarter turn style. They are incompatible with more than 10 percent ethanol fuel.
Craftsman gas caps feature vented models, 2-inch and 1.75-size models and models not for use with tanks holding more than 10 percent ethanol fuel.
The Troy Bilt gas caps come with vented options, up to 3.25-inch models and CARB-approved tethered caps.