Blackwings have always been known for their iconic, replaceable, square erasers. To replace your eraser, slide the eraser and clip out of the ferrule, remove the clip from the old eraser, place the new eraser into the clip, and insert the new eraser and clip into the ferrule. Replacement erasers come in sets of 10 and are available in black, white, pink, green, blue, navy blue, orange, yellow, red and grey.