Two-tier. These versatile racks are autoclavable and can be used dry, in water baths or in freezers. Each rack has an alpha- numeric reference for easy sample identification. Can accommodate 100 x 1.5ml tubes with closed caps or without caps, and 50 x 1.5ml tubes with open caps. Racks are stackable even when loaded and have (purpose) designed label spaces on each side (for bar coding, etc.).