Uni Filter Multi-Stage Competition Air Filter NU-4140ST

The principal of how foam air filters work is simple: "Open Cell" polyurethane foam is wetted with specially developed filter oil. The "sticky" filter oil is suspended in the path of the dirty air on the strands of the web-like cell structure of the foam. This makes it impossible for the dirt to pass through the strands. As the outer strands become loaded with dirt particles, the wetted strands down stream start trapping dirt, allowing the entire thickness to be utilized. This prevents surface loading or air restriction for 80% of the surface life of the air filter element. When the filter is sufficiently dirty it can be easily washed, re-oiled and re-used.

• Clean easily with grease-cutting dishwashing detergent; just clean, oil and reuse indefinitely
• Two-stage air filters come apart for maximum airflow and ultimate cleaning
• Most filters feature the Ultra Seal grease groove on the sealing surface
• Unsurpassed in airflow, stopping dirt and overall performance
• Each fits in stock airbox exactly like OEM filter
• Made in the U.S.A.