ins. should be for inserto (insert) and may refer, afaik, to the hexagonal inserts for screwdrivers (but normally with inches dimensions, unless this refers to a tapping tool) or to the threaded inserts used as rivets, but in this case I can't see how it could be with an external (maschio=male) thread.
pen. is likely for penetration, and could be a variant of an insert.
You should better describe your product or supply a reproduction of the label to get more help.