The wix 51100 cross reference to Napa 1100 and the fram c4 as well as the k55a krawlinater and probably many more the filters are getting more expensive lately. I was lucky to find the Fram in stock at Canadian tire for 8 bucks each so I purchased all they had but I liked the krawlinater filter as they had better gaskets a rubber ring gasket and fiber gasket for the top bolt
