Used up a full gel pen cartridge? Don't throw it away when you could just refill it! These rainbow ink refills fit the following pens from our store (but please note these are not erasable!): Pastel Rainbow Gel Pen Moomins Erasable Gel Pen Ombre Erasable Gel Pen Kitty Gel Pen* Cactus & Succulent Gel Pen* Cactus Gel Pen* *Please note these pens do not have frixion erasers on their barrels but still fit these cartridges. Perfect ink for bullet journalling as the ink sits on the surface of the page and won't bleed through. Dries quickly to a matt black finish. 0.38mm line width - excellent for every day usage. This listing is for one pen refill in BLACK.