This general-purpose invisible UV ink marker by DirectGlow goes on invisible and glows blazing bright blue in UV blacklight. Constructed of aluminum alloy with a spring-loaded nib, this marker is tough and sturdy. A solid plastic snap on cap keeps everything safe when not in use. Alcohol based and designed to dry fast; this ink is ideal for a variety of security purposes as well as casual fun use. Great for admissions, verifications, secret messages or glow parties, this marking pen is an all on one solution. Proudly made in the USA. Best viewed in low light, our ink is skin safe when used as directed. Does not wash off easily and tough to remove. Works best on porous surfaces. Not for printers or tattoos! Ultraviolet light required. Does not glow in the dark on its own. Nontransferable making it ideal for application to an already printed surface. Check for authentic returns, identify a thief, doodle invisible UV responsive designs on your skin, create unique art, use with escape rooms and so much more!