Hero Arts Reactive Inks are ideal for use with stamps and also for creating colorful backgrounds. The unique ink reacts to water when sprayed, dripped, or misted. The raised pad, measuring 3.5" x 2.25", easily inks stamps of any size. Non-toxic, long-lasting, quick-drying, and acid-free. Give your ink pad a refresh by refilling with NK436 Root Beer Reactive Ink Reinker.