There is no expiration -Two years is the shelf life. There is a lot # on the bottom of the box. This is an example of how it is coded;
Lot #02355B
023 Julian date of manufacture of batch (the 23rd day of 2015)
5 Last digit of year of manufacture of batch
5 Sequence of manufacturing batch for the day
B Second production run
So the shelf life for this batch is till January 23, 2017