Master Unit Slide Storage Boxes contain six boxes within a box. They can store 2,160 slides in easily identifiable groups within our Microchamber proactive conservation board. Each inner box (slide tray) will hold up to 360 slides. 35mm boxes come with neutral pH, non-buffered alpha cellulose index tabs to separate slides into eighteen groups; these boxes also feature our follower block system, which prevents slides from shifting in partially filled boxes. Full depth lids add extra protection, strength and security. Includes six complete single boxes and a master box. Size: 18.5 inches x 16.8 inches x 2.8 inches - 470mm x 422mm x 74mm