Replacement Filter for Intakes:
51-30811 Pro Dry S (White)
54-30811 Progressive 5 Layer (Blue)
75-30811 Pro-Guard 7 (Yellow)

Filter Types:

Pro Dry S
New Pro Dry S synthetic dry-media filters. Pro Dry S filters use a revolutionary two-ply synthetic material that is functionally superior to traditional paper media and single-ply synthetic, and easy to service. Pro Dry S dry-media filters increase airflow providing improved horsepower, torque, and fuel economy with 99.4%* filtration efficiency. Perhaps the greatest benefit of new Pro Dry S filters is the convenience of servicing these oil-free filters. To clean a Pro Dry S filter lightly tap it on the ground, vacuum it, or wash with soap and water. Solvents and oiling are not necessary.

Progressive 5 Layer
This new filtration technology is aptly called Progressive 5 Layer.  5 layers of progressively finer mesh medical grade cotton gauze with micro fibers that attract smaller and smaller particles as air passes through.  These 5 layers of cotton gauze is sandwiched between 2 layers of epoxy coated aluminum wire mesh.  

Pro-Guard 7
To address the need for extra protection from dust and dirt with washable/reusable oil-impregnated cotton gauze filters, aFe developed a new filtration technology so revolutionary that we applied for and received a patent.  This new filtration technology is aptly called Pro-GUARD 7.  5 layers of progressively finer mesh medical grade cotton gauze with micro fibers that attract smaller and smaller particles as air passes through is combined with 2 layers of random-porosity non-woven synthetic polyester fabric.  These 7 layer combination of cotton gauze and non-woven polyester is sandwiched between 2 layers of epoxy coated aluminum wire mesh.