Snaps easily into place Never needs sharpening PRODUCT DETAILS This is a refill cartridge for the Automatic Brow Pencil Duo.Snaps easily into place so you can change shades in an instant. Custom Tool The snap-in, snap-out cartridges let you create your own custom eye tool. For example, if you have an Automatic Brow Pencil Duo in one shade, try a refill in a second shade. Or add an Automatic Eye Pencil refill for brow color and eyeliner in one. Just snap out the brush cartridge and snap in the second shade for an ultra-convenient and very versatile tool. FORMULA FACTS Dermatologist-tested Ophthalmologist-tested Fragrance-free