Dual stage foam: Two different pore sizes create more trapping area for even the smallest dust particles
Flame laminated foam: Both “stages” are not glued, but heat sealed to provide maximum air flow
Reticulated foam: Increases dirt stopping surface area and increase foam strength
Strongest glue seams will withstand harsh solvents and gas (although we can’t understand why you’d want to use them). Pull as hard as you can, foam will rip before the glued seam will
Light color foam easier to spot where the filter oil has covered and where it has not
OEM size for more dirt stopping capability
Handmade
Every square inch of each filter is and inspected for quality
