Rite In The Rain All Weather Pen RefillRite in the Rain All Weather Pen ink refill cartridges will write for a considerable amount of time. When your ink finally runs out, this refill will get your trusty All Weather Pen back into the field. Dont worry about the refill fitting your pen; most Rite in the Rain All Weather Pens use the same pen refill style. This pen refill is 3 1 2" long with black ink.