Ultraviolet light and highlighter pens

A few weeks back, we had fun playing with infrared light , remote controls and black pens (some of which absorb infrared as well as visible

Ige Ultraviolet UV Spy Pen Highlighter Marker Invisible Ink Security Felt Pen (Blue)

Wrapables Invisible Ink Pen with UV Light, Spy Pen for Writing Secret

Opticz XL Invisible UV Blacklight Reactive Large Tip Ink Marker – DirectGlow LLC

Magic Highlighter Invisible Ink Pen Creative Marker Pens Built in UV Light Message Writing Ballpen - China UV Light, Ink Pen

DirectGlow Invisible UV Ink Marker Pen with Ultraviolet LED Keychain Blacklight : Office Products

Ossicones and oxygen

1pc Random Color Highlighter Pen With Light, Glow In The Dark Uv Magic Marker Pen For Invisible Fluorescent Marking

DirectGlow Invisible UV Ink Marker Pen with Ultraviolet LED Keychain Blacklight : Office Products

Our permanent UV Marker Pen leaves just a clear (invisible) mark when viewed under ordinary light. Under UV (blacklight) though, the writing glows

Invisible UV Marker