K&N High-Flow Clamp-On Universal Air Filter RE-1040 — 4" Flange, 7.5" Height, Washable High-Flow Performance

The K&N High-Flow Original Lifetime Universal Clamp-On Air Filter (RE-1040) is a washable, reusable oval-tapered filter built to boost airflow and last for the life of your vehicle.

This clamp-on filter is a universal solution for many intake setups where a 4-inch flange and a 7.5-inch height fit best. Designed with multi-layer cotton media and a pliable molded flange, it replaces disposable filters and provides a serviceable path to improved airflow for cars, trucks, motorcycles, and custom applications. The RE-1040 balances filtration efficiency with airflow, and comes pre-oiled and ready to install for a quick upgrade without complex modifications.

How does this filter affect engine breathing and performance?

The RE-1040 is engineered to open airflow compared with many paper elements while still trapping fine particles. Increased airflow can improve throttle response and support steady power delivery under load. Results vary by vehicle and installation, but many users report smoother acceleration after switching.

• Multi-layer cotton gauze media for higher air throughput.
• Pre-oiled surface to aid initial filtration without extra steps.
• Oval-tapered shape helps fit a variety of intake geometries.
• Designed to reduce flow restriction compared to standard disposable filters.

What are the dimensions and fitment details I need to know?

This clamp-on unit features a 4-inch (flange) diameter, a 7.5-inch overall height, and a 1.5-inch flange length—measure your intake tube to confirm compatibility. Its oval-tapered silhouette fits applications that require a compact footprint at one end and wider filtration area toward the top. Check clearance in tight engine bays to ensure the filter won’t interfere with nearby components.

• 4 in flange diameter for clamp-on installation to various tubing.
• 7.5 in filter height useful for limited vertical space.
• 1.5 in flange length for secure clamping and vibration absorption.
• Oval tapered body to adapt to uneven intake locations.

How do you maintain and clean the K&N RE-1040?

Maintenance is simple: remove, wash with a K&N cleaner, rinse, dry, and re-oil. Under typical highway driving, the filter generally only needs deep cleaning around long intervals—saving both cost and waste versus disposable elements. Always follow K&N’s cleaning and re-oiling guidance to preserve filtration performance.

• Clean intervals commonly around every 75,000 miles under normal highway conditions.
• Use K&N cleaning kit for proper wash and re-oil steps.
• Inspect more often in dusty or off-road environments.
• Reinstall with a secure clamp to maintain a tight seal.

Is this filter durable and backed by warranty?

Built with rugged materials and a flexible molded rubber flange, the RE-1040 is made to withstand vibration and repeated service cycles. K&N constructs its filters to be reused for years rather than disposed of after a single use. The product ships with a one-year limited warranty and is manufactured in the USA for consistent quality control.

• Durable molded rubber flange absorbs vibration and eases installation.
• Premium construction intended for long-term reuse.
• 1-year limited warranty supports manufacturing coverage.
• Made in the USA for trackable production standards.

Who is this for: The K&N RE-1040 is suited for DIY mechanics, custom fabricators, and vehicle owners who need a compact universal clamp-on filter with a 4-inch connection and oval-tapered body. Choose this filter if you want a washable, performance-oriented element that reduces recurring filter purchases and landfill waste while supporting improved airflow in many intake setups.