5/16-18 Hex Reversible Lock Nuts Grade 2 Steel Zinc Plated. Also called center lock nuts. Larger quantities are available, please inquire. All items are packaged in heavy duty ziptop bags and well labeled, perfect size for bin restocking! We carry 1000's of other fasteners in stock for immediate shipment. We have over 50 years of experience serving Metro Detroit. Send us your requirements. For prompt Quotations, E-mail; sales at americanintegratedsupply dot com or visit us at; www dot americanintegratedsupply dot com