This document provides devices and methods for monitoring and maintenance of the temperature of medical reservoirs and boxes in a secure fashion that enables for documentation of a chain of custody and history of temperature while in storage or transit. For example, this document provides devices and methods for monitoring the temperature of blood in phlebotomy tubes or boxes of biological products. In some embodiments of the devices and methods, the temperature of the contents of the medical reservoirs are regulated, modulated, and/or maintained by the devices provided herein.