Two-sided puzzle-shaped pieces hold an assortment of 1.5/2.0, 15 and 50 mL test tubes. Pieces can be used separately for small sample applications or connect in a square or row configurations. Imprinted references aid with easy retrieval of tubes. Bold assorted colors: yellow, blue, green and orange for quick identification. Constructed of robust polypropylene. Autoclavable . Each rack measures 151 x 135 x 66mm. Pack of 4.