[Harrak01 (OP)]

Hello,
Iám searching for a invisible  ink pen that will be invisible to the naked eye.
But will be visible with special glasses.
I found the  ADVANCED INTELLIGENCE SPY SHOP but they don't sell a ink pen but only the ink.
And put a cotton bud or Q-Tip in to the ink and use it
I want too write a letter, and need a pen.
Can someone give me a hint what to do.
Thx

GrK

[Don_1]

Buy a fountain pen. You'll probably find many on offer on eBay or any half respectable stationer or craft shop will stock them.

The advanced intelligence spy shop you found obviously isn't so advanced or intelligent if they sell ink but not pens.

Here you are :- Fountain pen on eBay. Quite expensive though, it will cost you a whole $0.01 or £0.01 and shipping from HK is FREE!!!

[CliffordK]

Of course, if you are too cheap to buy a S $0.16, £0.10 Fountain pen (undoubtedly the bid will go up a bit).

You could try a feather.  Look up "quill Pen" on the internet.

One problem with most of the "new" fountain pens is that they use an ink cartridge.  If you found an old one, it would have an ink bladder which may be easier to deal with.  However, find a 100 year old ink bladder, and it may need some maintenance.

Perhaps you could refill an ink cartridge using a syringe.  For that matter, perhaps you could refill a good many types of pen ink chambers with the syringe.  I'm not sure about sealing the ink chambers.

[RD]

You can buy the playing-cards already marked ...

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