When it comes to planning an event or running a business, stamps are a helpful addition to your arsenal for many reasons. When running an attendance-based business, hand stamps let you show important information such as guests under the drinking age or proof of admittance in place of tickets. Whether at a nightclub, theme park, or other themed event, invisible ink products can add an extra element of fun to the party. With this type of ink, also called UV ink, it will only show under a blacklight.