Eel Turquoise 3 oz fountain pen bottled ink by Noodler's Ink® [Eel series]
All "Eel" inks are bulletproof/waterproof. "Bulletproof" refers to any Noodler's Ink that resists all the known tools of a forger, UV light, UV light wands, bleaches, alcohols, solvents, petrochemicals, oven cleaners, carpet cleaners, carpet stain lifters, and of course...they are also waterproof once permitted to dry upon cellulose paper. Some inks are more bulletproof than others - generally in descending order (most bulletproof with the most testing - to less bulletproof): blacks, blues, yellows, invisible ("blue ghost" and "White Whale"), greens, browns, purples, reds....all are equally bulletproof with one exception: the resistance to strong industrial bleaches to the point where the paper structure itself decomposes. Reds are prone to more fading when exposed to strong bleaches (sometimes fading to a yellow) than the other colors.
For specific ink properties, we will refer you to the following Noodler's Ink® url:
Quality guaranteed by Noodler's Ink.
As a certified retailer for Noodler's Ink® I am able to only list their products at their recommended MSRP or allowed discount. Other certified retailers of this manufacturer are given the exact same guidelines. Should you see prices under the MSRP, I would caution you as to whether or not you are receiving an item from a certified retailer of this manufacturer. Purchasing items from non-certified retailers may invalidated your guarantee. However, only the manufacturer can address that issue with certainly. Remember buying below MSRP may not actually represent a "savings".