Generally, cryovials are made out of USP grade VI polypropylene. They are usually non-pyrogenic and DNase and RNase Free.
What is cryogenic vial?
Small, capped vials designed to withstand ultra-low temperatures; various capacities; may be sterile, non-sterile, and/or autoclavable; includes internally and externally threaded vials; ideal for sample storage in vapor state liquid nitrogen.