Eternal Polar Black resists the effects of time - moisture humidity UV light acids water exposure and many common detergents such as dish soaps and household ammonia as well as alcohols and acetone.
Polar Black as with all Noodler's ink is water-based pH neutral and will easily wash off your pens.
This listing is for a 4.5 oz. eyedropper glass bottle of Noodlers ink in Polar Black. Pen is a clear plastic so ink supply is visible.