The K&N RD-0700 is a round straight universal clamp-on air filter with a rubber top and cotton gauze media. Multiple layers of premium cotton gauze treated with a specially-designed tacking agent make up its filter element. It measures a 2-1/2 inch flange, 3-1/2 inch outside diameter, and 4 inch height, so it suits custom intake tubes, carbureted builds, and off-road or equipment applications rather than one specific factory airbox. K&N markets its universal line for racing vehicles, radio-controlled cars, generators, snowmobiles, tractors, and other applications.
Washing and re-oiling this filter replaces repeated paper-filter purchases, which is where the price pays off. The manufacturer lists a Washable · Yes design with a 0.34 oz (10 ml) re-oiling amount and states filtration efficiency of up to 99%. The molded rubber flange is designed to absorb vibration while holding firmly on the intake, which matters on a track or off-road setup where engine vibration is constant.
Because the filter is universal, fit depends on matching the flange to your intake. The manufacturer notes the flanges can also be stretched for up to 1/16 of an inch (1.5mm) to fit in-between sizes. Search terms buyers commonly use include "2.5 inch flange universal clamp-on air filter," "round straight K&N washable air filter," and "RD-0700 carburetor air filter."
The manufacturer offers a carburetor adapter flange that adapts a K&N Universal Filter to a carburetor with a flat flange. Check your carburetor's flange style before ordering.
According to the manufacturer, this filter is washable and reusable. It is pre-oiled, and the manufacturer specifies a re-oiling amount of 0.34 oz (10 ml) after cleaning.
The manufacturer's listing shows a 1 year limited warranty. Warranty terms vary across sources, so confirm current coverage directly with the manufacturer before purchase.
This is a low-difficulty, clamp-on install that typically needs only a hose clamp and the appropriate intake connection. Confirm that the 2-1/2 inch flange matches your intake tube or adapter, using the 1/16 inch stretch only to close small size gaps. The manufacturer advises against accordion-style flex hose between the filter and the throttle or carburetor, because it restricts airflow and is difficult to seal, so use a smooth bore hose instead. If your carburetor uses a flat flange, the manufacturer's adapter flange is the intended connection.
