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The K&N Engineering RU-4250 Universal Rubber Air Filter is designed for a wide variety of applications, including racing vehicles, radio-controlled cars, generators, snowmobiles, tractors, and other equipment. Its universal design accommodates air intakes with different angles and offset diameters.
Constructed with an ultra-strong, molded pliable rubber flange, this air filter helps absorb vibration and provides secure attachment. The flange can stretch up to 1/16 inch to help fit between sizes, offering added flexibility during installation.
The K&N RU-4250 is washable and reusable for continued service. An optional Air Filter Foam Wrap and Filter Care Service Kit are listed as associated products. This product is not CARB approved, and a CARB acknowledgement is required.
The filter is backed by a 1-year limited warranty. The product data also identifies it as an automotive part and indicates a Prop 65 designation.
Features:
Order Processing
All orders are processed and shipped within 24 hours of purchase (excluding weekends and holidays).
Orders placed after 3:00 PM EST may ship the following business day.
Shipping Methods
Customers select their preferred shipping method and speed at checkout.
Shipping times are determined by the carrier and cannot be guaranteed by us.
Tracking information will be provided once your order has shipped.
Shipping Coverage
If your package arrives damaged, please notify the delivery driver immediately and contact the shipping carrier to file a claim.
You must report any missing or damaged items within 14 days of delivery.
After this time, we cannot be held responsible for lost or damaged items.
Return Window
You have 30 days from the date of delivery to request a return.
After 30 days, we are unable to accept returns, exchanges, or refund requests.
Eligibility
Items must be returned in their original condition—unused, unwashed, and with all tags and packaging intact.
Certain products may not be eligible for return (e.g., special-order items, customized products, or perishable goods).
Items that have been altered, installed, or modified cannot be returned.
Return Process
Contact our Customer Support team to request a Return Authorization (RMA) before sending items back.
Once your return is approved, you’ll receive instructions on where to send the product.
Customers are responsible for return shipping costs unless the item was defective or incorrect.
Refunds
Refunds are issued to the original payment method once the returned item has been received and inspected.
Please allow 5–10 business days for the refund to appear on your account.
In some cases, a restocking fee may apply (if applicable, this will be disclosed during your return authorization).
