Completely airtight and moisture-proof. Made of highly polished 18‚Äì8 stainless steel, with three sides of 4.75mm (3/16") glass. "Sealtight" door. Manual relief valve normalizes pressure in cabinet before opening door. Indentations on top surface for stacking and storing. Exterior: 41.9W x 58.4L x 56.5H cm (16¬Ω x 23 x 22¬º") Has two height-adjustable, stainless steel shelves: 48.3W x 34.3L cm (19 x 131/2") and a stainless steel tray: 30.5W x 41.6L x 5H cm (12 x 16‚Öú x 2") for holding desiccant or instruments.