I was also looking at data loggers lately. The most important criteria in our evaluation were the durability of the loggers, the size of the loggers (we want to place the logger directly in the product. The small volume of the logger is important to avoid its own mass to influence the measurement) and the possibility to exchange the battery by the user. NIST traceability is definitely a must for me and I require conformity to 21 CFR Part 11 since the data loggers are for use in the pharmaceutical industry. Finally the operating temperature must range from ca. -70°C (validation of refrigerators) to up to 140°C (validation of autoclaves). I did my research and found there are a lot of brands out there but very little which fit all the above mentioned criteria. The Tracksense Pro Logger from Bakrona / Ellab (www.bakrona.ch/produkte/thermische-validierung/drahtlose-datenlogger/datenlogger.html) seem the best fit so far. From what I understand the software is validated and can be used to generate reports according to EN ISO 17665 / EN ISO 15883. I also know that nowadays most of the large pharmaceutical companies use these Loggers. Hope this is helpful
