This expandable 4-part rack system holds, 50mL and 15mL centrifuge tubes, micro centrifuge tubes, culture tubes, PCR tubes, and plates, and culture tubes. You can assemble it into the configuration that works for you. You can add additional sections to fit your needs. Autoclavable (122°C) and freezable (-190°C). Includes purple, yellow, blue and green sections in package. Made in USA.