5/16"-18 Square Nut - Stainless Steel 18-8

Marsoni

M251S

$40.86

Get it in 3 business days with 1 day shipping. Friday, May 29

5/16"-18 Square Nut - Stainless Steel 18-8Product Details : 5 16" 18 Square Nut Stainless Steel 18 8 Product Type: Square Nut Thread Size: 5 16" 18 Bolt Diameter Size: 5 16" Thread Count (Pitch TPI): 18 Thread Type: Coarse Imperial Thickness: 7 32" Tool to use: 9 16" Material(s): Stainless Steel 18 8 Material Grade: Thread Fit: Unified Standard Class 2B For any information about products, please contact us. *Photos for reference purposes only.

Easy Shipping

Quick Dispatch:

Your 5/16"-18 Square Nut - Stainless Steel 18-8 orders ship within 1-2 business days.

Delivery Options:

Standard: 3-7 business days
Fast: 2-3 business days
Express: 1-2 business days

Order Tracking:

You'll receive a tracking link by email once your 5/16"-18 Square Nut - Stainless Steel 18-8 ships.

Need Help?
Questions about 5/16"-18 Square Nut - Stainless Steel 18-8, sizing, or delivery? We're just an email away.

Live Shipping Estimates:
Enter your location at checkout to see available shipping methods and costs for 5/16"-18 Square Nut - Stainless Steel 18-8 in your area.

Get Shipping Estimates

Country Zip/Postal Code

Exchange/Return Notes

We offer a 30-day return/exchange service after receiving.
Final sale items are not eligible for returns or exchanges.
To process your return/exchange, please contact us at [email protected]
Please click here for more details>>> Return & Exchange Policy

This filter looked about the same as the OEM filter. It installed in about a minute. The quality appeared to be fine. It was protected in a cardboard box. It fit my 2014 Subaru Outback perfectly. I just installed it an hour ago so I don’t have any long term observations about longevity or effectiveness. I can’t see any reason why it would not work as well as the original, it seemed identical.

WAS THIS REVIEW HELPFUL?YesReportShare

Reviewed in the United States on May 29, 2026

Verified Purchase

Nicholas K

Cuba, US

★★★★★ 5

Great filter

Size: AF259

This fit my Mazda CX-5 perfectly. I'm happy with the seal and quality. Great price. I will certainly reorder for my next replacement.

WAS THIS REVIEW HELPFUL?YesReportShare

Reviewed in the United States on May 19, 2026

Verified Purchase

Amazon Customer

Grantham, US

★★★★★ 5

Great fit and quality

Size: AF113

Not a complicated product, but after going to 2 different auto parts stores and this not being in stock, Amazon to the rescue. Arrived the next day and the quality is definitely on par with “store brand” ones from retailers. Definitely cheaper as well.

WAS THIS REVIEW HELPFUL?YesReportShare

Reviewed in the United States on April 23, 2026

Verified Purchase

Alexandria, US

★★★★★ 5

Fit my 2014 Accord perfectly

Size: AF476

Seems to be the same quality as OEM. Fit perfectly. Easy to install.

WAS THIS REVIEW HELPFUL?YesReportShare

Reviewed in the United States on April 24, 2026

Verified Purchase

Becca