Traditional data loggers in refrigerated vehicles simply monitor the ‘air-on’ and ‘air-off’ temperatures from the refrigeration unit which is a good indicator as to whether the refrigeration unit is working but of little if any value in understanding the ‘holding’ temperature of the product. DAN data loggers probe for temperature at various points inside the vehicle and always include a SIMULATED PRODUCT TEMPERATURE probe enabling transport companies and product owners to better understand the relationship between air temperature and product temperature.