The Pen+Gear Deposit Bags distributed by National Distribution Warehouse are for secure transfer of coins and valuables. The anti-fraud technology which is one of the highest security levels as it incorporates both heat and cold-indicating technology. Cooling agents cause VOID graphics to appear on the closure. If heat sources are used blue dots appear to indicate tampering. Inked self-sealing closure which will deform if tampered with. Patterned and serrated edge closure system to promote fracturing in the event of a tampering attempt. Extruded plastic is very resistant to tearing and cannot be smoothed back to its original state if tampered with. Sender and receiver instructions written on the bag. Each bag has a unique deposit number with a scannable code for keeping track of your deposits. Peel-able receipt label on the inside of the closure.