> In 1998, ISO came up with some standards for pens. ISO 12157 is about ballpoints. 12157-1 deals with refill sizes. Parker ballpoint refills became one of the standards size, namely G2 (Not to be mixed with Pilot G2s). There is D1, A1 and other types. Physical sizes are in this standard. 12157-2 is the strength of the ink to removal such as chemical, water, sunshine and so on. So if a refill is ISO 12157-2 certified, then you can safely sign a document knowing that it will be harder to remove (not impossible) than a non ISO 12157-2 ballpoint refill.