Check the listing for details. 1/4-28 Acorn Cap Nuts Stainless Steel 18-8 Standard Height Quantity 500. Condition: New. Listed at 129.62 USD. 1/4-28 Acorn Cap Nuts Stainless Steel 18-8 Standard Height Quantity 500 Acorn nut is its common name and it is also called a crown hex nut, blind nut, cap nut or domed cap nut. It is a nut that has a domed top to cover the threads.This is to prevent contact with the external thread to protect the threads or protect other things the threads would rub against. In addition the dome gives a more finished appearance.nuts and bolts General Product Information Drive Style : Socket Drive Size : 7/16" Thread : 1/4-28 Material : Stainless Steel 18-8 Quantity of Fasteners in Package : 500 Detailed Product Information: Width - Flat to Flat : 7/16" Overall Height : 15/32" Width - Point to Point : 0.505" Threads Per Inch (TPI) : 28 Thread Depth : 0.350" Coarse or Fine Thread : Fine Thread Direction : Right Hand Shipping: All orders placed before 3:30 pm EST Will Ship Same Day Tracking is provided on ALL Orders Priority Mail Shipping service is offered at a discount of only $3.95 UPS Ground UPS Next Day Air is available, Please inquire for pricing Returns : ALL returns are accepted if returned within 60 days. Money Back or exchange guaranteed. NO Restocking Fees. For YOU, we constantly strive to find ways to improve our performance.