aFe 21-40011 Magnum FLOW Pro DRY S Conical Air Filter 4 in x 6 in x 7 in

Vehicle Fitment

• Universal conical clamp-on air filter - fits any intake system using a 4-inch (102mm) inlet tube or connection point
• Compatible with cold air intake systems, diesel intake pipes, turbo inlet pipes, and custom intake builds requiring a 4-inch flanged conical filter
• Commonly used on diesel truck intake systems (Cummins, Powerstroke, Duramax) and high-displacement gas engine builds with 4-inch intake tubing

Fitment Notes

• The 21-40011 is a universal clamp-on conical filter - fit is determined by the 4-inch flange inlet diameter. Confirm that the intake tube or connection point on your application measures 4 inches (102mm) OD before ordering.
• This is the Pro DRY S oil-free synthetic version - no filter oil is required at installation or after cleaning. The 21-40011 is ideal for diesel and gas applications where MAF sensor protection from oiled media overspray is a priority, and for owners who prefer a low-maintenance filter service procedure.
• A coupler is included for installation on the intake tube.
• The companion Pro-GUARD 7 oiled version in the same 4 x 6 x 4-3/4 x 7-inch dimensions is aFe PN 72-40011, for applications where maximum filtration efficiency in severe-duty off-road environments is preferred over the oil-free convenience of the DRY S.
• Sold individually - one filter per package.

Features

• Pro DRY S Three-Layer Oil-Free Synthetic Media - Optimum Filtration and Flow: The 21-40011 uses aFe's Pro DRY S filter media - three layers of progressively finer mesh synthetic material delivering high airflow performance without requiring filter oil. The progressive multi-layer construction provides optimum filtration efficiency and consistent flow even when the filter is dirty, making it suitable for extended service intervals on street-driven vehicles, daily-use trucks, and performance builds alike.
• Large 4-Inch Inlet - High-Volume Airflow for Diesel and Big-Displacement Applications: The 4-inch flange inlet diameter accommodates the large-diameter intake tubing used on diesel trucks (Cummins, Duramax, Powerstroke) and high-displacement naturally aspirated and forced induction gas engines where maximum airflow volume is critical. The 6-inch base provides a large filter face area to match the high airflow demand.
• Tall Conical Design - 7-Inch Height for Maximum Media Surface Area: The 7-inch filter height with 6-inch base tapering to a 4-3/4-inch top provides substantial conical filter surface area for excellent dust-holding capacity and extended service intervals. The tall conical geometry maximizes the ratio of filter media area to inlet flange size - delivering more filtration capacity than a short cylindrical design.
• Integrated Bump Seal - No Sealants or Gaskets Required: The 4-inch flange features an integrated bump seal that conforms to the intake tube when clamped, creating a positive no-leak seal without sealants, tape, or gaskets. The bump seal always returns to its original form, maintaining sealing effectiveness across multiple installation and removal cycles.
• 100% Polyurethane Frame - Full 360-Degree Urethane Construction: The full 360-degree urethane frame with polyurethane top and base provides structural rigidity, dimensional stability, and resistance to diesel fuel, oil, and under-hood heat - maintaining dimensional accuracy and seal integrity across the operating temperature range.
• Washable and Reusable - Low Maintenance: Clean with aFe's Pro DRY S filter cleaner, rinse with water, and allow to fully air-dry before reinstalling - no re-oiling required. Multiple cleaning cycles are supported without media degradation, eliminating the cost of disposable filter replacements over the service life of the intake system.

Specifications

• Part Number: 21-40011
• Brand: aFe Power (Magnum FLOW series)
• Product Type: Universal Conical Flanged Clamp-On Air Filter
• Filter Media: Pro DRY S - Three-Layer Oil-Free Synthetic
• Flange / Inlet ID: 4 in (102mm)
• Base OD: 6 in (152mm)
• Top OD: 4-3/4 in (121mm)
• Height: 7 in (178mm)
• Filter Style: Conical, flanged, clamp-on
• Frame Material: 100% Polyurethane - full 360-degree urethane frame
• Seal: Integrated bump seal (no sealants or gaskets required)
• Oiling Required: No (Pro DRY S - oil-free synthetic media)
• Washable / Reusable: Yes
• Coupler Included: Yes
• Fitment: Universal (4-inch inlet)
• Quantity: 1 (sold individually)

Included Components

• 1x aFe Magnum FLOW Pro DRY S Conical Air Filter (21-40011)
• 1x Coupler

Product Description

The aFe 21-40011 is a Magnum FLOW Pro DRY S universal conical clamp-on air filter in the 4 x 6 x 4-3/4 x 7-inch configuration - one of aFe's most popular large-inlet universal filters for diesel trucks and high-displacement gas engine intake systems requiring 4-inch inlet tubing. The Pro DRY S three-layer oil-free synthetic media delivers maximum airflow without requiring filter oil, making it ideal for MAF-equipped engines and any application where low-maintenance oil-free filtration is preferred.

The 7-inch tall conical design with 6-inch base provides generous filter surface area for excellent dust-holding capacity and extended service intervals. The full 360-degree polyurethane frame and integrated bump seal provide a positive no-leak connection without sealants or gaskets. Washable and reusable with aFe's dry filter cleaner - no re-oiling required. Coupler included. Universal fit for 4-inch inlet applications.