This ProMag AK-223 magazine is constructed of a proprietary polymer to ensure a long service life. Additionally, the spring is a heat-treated, chrome-silicon wire for consistent and smooth feeding. ProMag magazines include a lifetime guarantee, if you ever have a problem with their magazines, simply return them to ProMag for replacement. Product Specifications Capacity: 30 Rounds Caliber: .223 Remington and 5.56x45 NATO Material: Steel-Lined Polymer Color: Black Made in the USA