Lightning Powder Evidence Security Bags feature a special, extremely strong tamper indicating adhesive that, once opened, will not reseal. The word EVIDENCE” is printed around the borders of the bag. If the bag is opened, then heat-sealed closed, the words will shorten or distort. The majority of the front panel is covered with a translucent white, which provides plenty of writing space. However, the back and the edges remain completely clear so that evidence is still easy to see. The top edge is perforated and has a matching control number. The top edge can be removed by the person sealing the bag and kept as a receipt.