Refill cartridge for the ultimate lip lining tool. Color twists up, never needs sharpening. Refill easily snaps into place. You can create your own custom lip tools using the Automatic Lip Pencil Duo, thanks to the unique snap-in, snap-out cartridges. For example, if you have an Automatic Lip Pencil Duo in one shade, try a refill in a second shade. Just snap out the lip brush cartridge and snap in the second shade for an ultra-convenient and very versatile tool.