The Hornady Security Square-Lok AR Upper Receiver Mount provides a simple, secure way to organize and store spare AR upper receivers on a Square-Lok panel. Its all-steel construction attaches at the upper receiver's rear takedown pin lug, creating a solid mounting point that drops securely into the Square-Lok system. Sold in a convenient three-pack, it helps keep spare uppers organized, protected and readily accessible. Designed for AR upper receivers, attaching securely at the rear takedown pin lug. All-steel construction provides a strong, durable mounting solution. Attaches securely onto Square-Lok panels for clean, organized storage. Sold in a three-pack for organizing multiple upper receivers. Size: 2.4"H x 1.4"W x 1.3"D