Autoclavable polypropylene (PP) Heavy-duty construction is durable and chemical resistant Multiple colors available for benchtop organization at a glance Versatile design accommodates different tube sizes on each side The four sides hold the following tubes: ​Eight (8) - 50mL or 30mm diameter tubes Twenty (20) - 20mm diameter Tubes Twenty Four (24) - 15mL or 17mm diameter tubes Forty (40) - 12mm diameter tubes *Note: Assorted Pack Colors: Blue, Green, Orange, Pink & Yellow