Where do i go to buy a good waterproof pen for drawing?

Question

i need a pen to work with watercolor and marker..

Answer 1

unipens or any with roller ball are good.Most stationery store carry them.

Answer 2

Any waterproof pen will work.  Most roller balls are permanent, although I know some run when wet.  Google "waterproof drawing pens" and I am sure you  will find many possibilities.