Originally Posted by JoBear2
Elzybells Art Stamps (UK) have an awesome white pen that is opaque: see this link
I have tried lots of different brands of white pens - and been disappointed time and time again because they weren't opaque enough and all but disappeared on coloured cs, or the ink didn't flow smoothly and it 'skipped'. The Elzybells ones rocks for me!!
That looks like the Inssentials pen.