These durable aluminum pens are refillable and offer archival, acid-free, pigment based ink. Tips can be replaced with standard SP nibs. The black pens are waterproof. Compatible with Copic markers.
Never throw an SP away, just replace worn nibs and insert refill cartridges in SP pens quickly and easily. One end is for nibs, the other for refill cartridges. Ink may take a minute to flow after changing a nib.