This review is by Kalina Wilson, who can also be found at geminica.com .   It can be hard to find a good brown pen for sketching.  While there are a lot of beautiful brown fountain pen inks, they aren't waterproof (with perhaps one or two rare exceptions).  
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Penversary Pen, wazzat? — The Pen Addict
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This Leather Zippered Pen Case has a velvet lined interior and holds up to 3 pens and a credit card or ID card. When you want to carry your favorite pens, you want them protected in your bag, purse or pocket. This leather pen holder is great to protect your fountain pens and keep them safe from leaking or getting scratched.
Leather Zippered Duo Slim Pen Case for 2 Pens - Crazy Horse Brown
The Pen Addict
The Pen Addict
The Pen Addict
Penversary Pen, wazzat? — The Pen Addict
The Pen Addict: My Favorite Five Fountain Pens
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The Pen Addict
The Pen Addict
The Pen Addict
Shop — The Pen Addict