K&N RU-5321 Universal Clamp-On High-Flow Air Filter 4.5" Flange Cone Filter

Vehicle Fitment

• Universal Fit - Designed for custom air intake systems with a 4.50 in (114 mm) outside diameter intake tube.
• Suitable for a wide variety of custom automotive, racing, off-road, powersports, agricultural, industrial, and stationary engine intake applications.

Fitment Notes

• This is a universal air filter and is not vehicle-specific.
• Verify flange diameter and available installation clearance before ordering.
• Requires a 4.50 in (114 mm) outside diameter intake tube.
• May require modification depending on the application.

Features

• Engineered with high-flow oiled cotton gauze media to improve airflow.
• Washable and reusable for long service life.
• Four layers of premium cotton gauze provide excellent filtration efficiency.
• Round tapered design helps maximize airflow while maintaining filtration.
• Flexible molded rubber flange provides a secure seal and absorbs vibration.
• Pre-oiled and ready for immediate installation.
• Designed to support improved horsepower, throttle response, and engine performance when properly installed.
• Heavy-duty construction for demanding street and competition applications.
• Rubber flange can accommodate slight size variations of approximately 1/16 in (1.5 mm).

Specifications

• Product Type: Universal Clamp-On Air Filter
• Filter Shape: Round Tapered
• Filter Media: Oiled Cotton Gauze
• Flange Inside Diameter: 4.50 in (114 mm)
• Flange Length: 0.625 in (16 mm)
• Base Outside Diameter: 7.50 in (191 mm)
• Top Outside Diameter: 4.563 in (116 mm)
• Overall Height: 9.50 in (241 mm)
• Flange Type: Centered
• Filter Color: Red
• Washable: Yes
• Package Quantity: 1

Included Components

• 1x K&N RU-5321 Universal Clamp-On Air Filter

Product Description

The K&N RU-5321 is a universal round tapered clamp-on air filter designed for custom intake systems utilizing a 4.50-inch inlet. Its premium oiled cotton gauze filter media delivers high airflow while providing excellent filtration, making it an ideal choice for performance street vehicles, race cars, off-road vehicles, powersports equipment, and other custom applications.

The molded flexible rubber flange provides a secure connection while helping absorb engine vibration for reliable performance. Unlike disposable paper filters, the RU-5321 is washable and reusable, allowing it to be cleaned and re-oiled for repeated use throughout its service life. Always verify inlet diameter and installation clearance before installation, as this filter is intended for universal applications rather than direct vehicle-specific replacement.