I have a Craftsman push mower with 21" cut and 6.5HP Briggs & Stratton motor. The original gas cap broke and I have bought probably 4 different "universal" caps to replace the original. None of the "universal" caps would fit and none of the local big box stores sell a Briggs & Stratton specific cap. I bought this cap and it fits perfectly. The original cap had the built in fresh start cartridges to keep your gas fresh and this one doesn't. Since day 1, I never bought the fresh start cartridges so no loss for me. Just add fuel stabilizer in your gas can and it does the same thing and it's cheaper.