Here is a brief overview on what buffer vials are and what they are used for.
Buffer vials from Tempalert are a thermal damper used to minimize temperature spikes. It reduces temperature spikes by 60% and can delay rapid change in temperature readings by 10-15 minutes.The buffer vial is only an accessory and does not include a temperature sensor.
Buffer vials are highly recommended for users monitoring vaccines and medications. For example it can reduce the occurrence of false alarm from opening cooler/freezer doors.