Noodlers Polar Blue
Polar Blue (Bulletproof & lubricating) 90ml Bottle of ink PH Neutral. Can be safely used in all brands of pens.
"Freeze Resistant Inks" include Polar Blue, Polar Brown, Polar Green and Polar Black, which will resist forming a solid mass of ice within a glass ink bottle during most cold weather conditions (though they will form some harmless ice "slush" when very cold).
All Noodler's Polar Inks are also classed as "Bulletproof", as well as such inks as "Lexington Gray", "Black", "Hunter Green", "Luxury Blue", "X-Feather", and "Fox Red". References to ink properties are generally printed upon the labels (with the exception of "X-Feather" - which is a white label issue with very little text).