What It Is:A customizable and refillable case for the new generation of Rouge G, Guerlain's iconic jewel lipstick (sold separately), which has been reinvented in an ultra-caring, skincare-based formula.What It Does:Boasting a secret double mirror, the new Rouge G cases come in an array of designs. Pair with the new Rouge G Customizable Lipstick Refill (sold separately) to design your complete lipstick. The new Rouge G cases are only compatible with the new-generation refills and vice versa.How To Use It:Customize your lipstick in two steps. For your first Rouge G purchase, choose a case and a shade (sold separately) to create your complete lipstick. For the following ones, refill the shade or change the case as you wish.