The SKB 3i-M4U20-FRM is a rugged 4U injection molded rack frame designed for 20” deep rack gear, built to offer superior protection and portability for professional AV, audio, and industrial equipment. Constructed from ultra-tough polypropylene copolymer resin, this rack frame is part of SKB's 3i Series and is resistant to impact, corrosion, UV, and extreme temperatures. It features integrated front and rear rack rails for secure mounting, molded-in handles, and precision-engineered design for seamless fit into compatible SKB 3i cases. Ideal for fly dates, touring, or mobile applications, the 3i-M4U20-FRM provides a dependable, lightweight, and secure rack solution.