ViewPoint™ microcentrifuge 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. ATP, RNase/DNase and Endotoxin Free (non-pyrogenic). With snap style flat cap. Holds 1.5mL. Polypropylene USP Class VI resin. Centrifuging to 40,000 x G. Freezable -80C. Autoclavable. 100 tubes per bag/5 bags per pack/1 pack per case. Patents Pending. Made in USA.