On my W-2 that box was used for the amount of money that was deducted from my income on a pre tax basis. In my case, my required safety shoes that I purchased was taken out of my pay checks weekly for the amount of $10. Over the period of a year I purchased 2 pair so that was part of my amount. Another pre tax item on mine was for dental and vision insurance deducted before taxes were taken out as well.
