Empatica devices are typically classified by customs agents under harmonized tariff heading 9029.20.40 as heart-rate monitoring devices. We have been advised that this is the proper classification based on the 2014 binding ruling N252454.
As of November 2015 this classification is listed as a free rate of duty on import to the United States. Should you still receive a payment notification from the courier please contact Empatica at the email address firstname.lastname@example.org so that we can provide you with all necessary documentation that shows that your order should be free of duty.
Empatica ships devices under incoterm "DAP" so if duties are assigned to your E4 order your institution will be responsible for any appeal to customs/border control. Empatica can provide supporting material for customs brokers representing your institution.