Prima Pens feature an EPA registered antimicrobial agent that is incorporated into the plastic which protects the pen by suppressing the growth of bacteria, algae, fungus, and mildew. -Antimicrobial inhibitors manufactured by world-renowned Sanitized®, Swiss Antimicrobial Expertise since 1935. -For more information on U.S. regulations on antimicrobial agents and treated products, visit https://www.epa .gov/safepestcontrol/consumer-products-treated-pesticides.