The enclosure houses, organizes, manages, and protects fiber optic cable, terminations, splices, connectors and patch cords. It accommodates all HD Flex™ cassettes, fiber adapter panels (FAP), trunk cables, connectors and patch cords. It provides front access with drawers that slide out into two locked positions, regardless of how many enclosures are stacked together. The enclosure tray allows half of the tray to operate independently, an ideal option for redundant networks. The enclosure allows cassettes and FAPs to be installed by dropping them into the front of the enclosure tray or sliding them into the rear of the enclosure tray which allows each individual cassette/FAP to be removed with minimal disruption to other cassettes/FAPs. The enclosure is constructed of steel material. Enclosures are ordered in either 4-port, 6-port, or 12-port cassettes configurations. Each enclosure is able to be adapted to accommodate all three different types of cassettes by adding/removing dividing rails.