Made of high-density polymer with temperature-resistant construction the Command Arms MCD16 Redesigned Magazine Coupler for CAA Polymer Magazines offers durability in the field. This coupler attaches 2 CAA 30-round magazines and features a spring-loaded design. Fits firearms that accept standard AR15 magazines. - Fits firearms that accept standard AR15 magazines - Attaches two 30-round .223 or 5.56 x 45mm CAA polymer magazines - Made of high-density polymer for durability and light weight - Spring-loaded design - Designed to keep counting window visible so you know how many rounds remain - Ambidextrous - Captive nuts - Temperature resistant for use in extreme conditions