The SKB 3i-M3U20-FRM is a rugged 3U injection-molded rack frame designed specifically for 20-inch deep SKB iSeries waterproof cases. Engineered with a high-strength, lightweight plastic construction, this frame features front and rear steel rack rails with a universal 10/32 threaded pattern, allowing for secure mounting of rack-mountable equipment. Ideal for touring professionals and field engineers, the 3i-M3U20-FRM ensures reliable protection against shock, moisture, dust, and impact, making it a dependable solution for safely transporting audio, video, and IT gear in challenging environments.