While not commonly used for applications with operating temperatures less than 100K, TAI's Graphite Fiber and PyroFlex graphite sheet thermal straps have both been used at cryogenic temperatures by customers at NIST and several companies in the medical and quantum computing industries. Unlike OFHC copper, the material thermal conductivity of graphite and graphene drop rapidly as temperatures fall below 100K, and depending on the material, they cease transferring heat and can even act as a thermal barrier between ~10K and 40K. However, because the conductivity is so much higher than copper and aluminum at temps as low as 80K, they can be used as a "non electronic or mechanical" thermal switch. Meaning that the graphite straps can substantially reduce cryocooler cool down times by transferring more heat than metallic thermal straps at operating temperatures of ~80K - 300K, but as the temperatures drop to 40-50K (in the case of graphite fiber straps), and 10-15K (for graphite sheet straps), the straps stop conducting heat (acting like a thermal switch).