Staples counterfeit detector pens provide a quick and easy way to verify bills in any cash handling environment. Identify fraudulent bills by using these Staples counterfeit detector pens on all your incoming cash. Each pen in this 12-pack features iodine-based ink that evaporates completely on legal bills but leaves a dark stain on counterfeits. Simple to use and providing immediate results, these Staples counterfeit detector pens are ideal to keep by every register or cash box. Counterfeit pens are designed to detect false currency. Black color for an attractive look. Sold as 12 per pack. Safety Data Sheet.