dual layers can flex to the restricted degree required to prevent the rigidity of for example plywood where the various layers are bonded together for practical reasons both of the two layers should have anchored ends and the inside or back up layer should have greater tear and tensile strength between the anchored ends than does the paper it supports preferably the back up layer or inside layer is a spunbonded non woven fabric made of filaments of plastic more resistant to the fluid temperature being filtered than is the filter paper because it works in tension and has high tear and tensile strength the inside or back up layer can be a fabric having substantially greater flexibility and lighter weight than does the filter paper its porosity should be greater than that of the filter paper the latter being relied on for filtration and the tensioned flexible back up layer being relied on to maintain the integrity of the filter paper when the dual media comprising the two layers operates under conditions which would otherwise cause destruction or undesired deformation of the filter paper application of these principles to an automobile engine oil filter for example with the two layers interpleated but the filter otherwise being possibly of the usual prior art construction provides an oil filter having an unusually extended service life in this case the pleated dual media can have its ends anchored by the usual filter element end.