ViewPoint™ centrifuge tubes visably signal the temperature of the tube and contents. Shifting to dark blue when the temperature of tube contents is below 0°C. This helps you keep better control over your work and can improve processing times.. At 5° C and above ViewPoint™ tubes are clear and transparent. At 4°C ViewPoint™ tubes transition to light blue and become slightly opaque. At 0°C ViewPoint™ tubes reach their full progressive transition to dark blue, are completely opaque, and provide protection from Ultraviolet (UV) light. Caps include integral molded elastomeric seal. 3 color printed graduations and reverse reading scale. ATP, RNase/DNase and Endotoxin Free (non-pyrogenic). Validated Sterilization (ISO 11137) for use in Research and Medical labs. Holds 15mL. Polypropylene USP Class VI resin. Centrifuging to 12,500 x G. Freezable -80C. Autoclavable. Teal color caps. 25 tubes per reusable polypropylene rack/2 racks per pack/6 packs per case. 17mm W. 118mm H. Patents Pending. Made in USA.