Controlled-rate freezer does not require expendable liquid nitrogen and the associated pumping, re-filling, and storage challenges posed by a cryogenic liquid. The unit simply plugs into a standard electrical outlet and quietly provides low temperature cooling to either -40ºC or -80ºC. Unlike liquid nitrogen systems which surround samples with a cold vapour phase, the freezer immerses samples into a well-circulated, cold liquid bath. The circulating liquid allows efficient heat transfer to the samples and maintains a consistent temperature profile at all locations. Typical applications include cryopreservation of human and animal embryos and biological tissue and cell lines.