Which invisible ink pens are best? Spies and conspirators have used invisible inks for millennia to send messages. In the modern age, invisible ink pens are an excellent way for grown-ups to ...
Need some gifts for your kids, grandkids, nieces and nephews? More specifically, gifts they won't toss aside as soon as they open them? We've got the goods: Maleden Invisible Ink Pens. These ...
A company called Apollo Japan has developed the so-called Speakun [JP], a pen-shaped device that’s able to read invisible codes printed on paper and then plays back pre-recorded sounds. Users first ...
Which invisible ink pens are best? Spies and conspirators have used invisible inks for millennia to send messages. In the modern age, invisible ink pens are an excellent way for grown-ups to ...
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