It's like a smart jump drive that is plugged into the credit card swiper and when purchases are performed the Derk keeps track of the purchase for multiple reasons. For exchange returns emailed to a boss. Keep track of for work deductible. Can be emailed to work for sales reports. Traveling expenses. No more lost receipts or coffee spill stains on them. And the Derk can be read by the stores for return purposes and by the owner's computer but not altered. Could also save millions of trees.