I bought this face massage roller at a shop in Far East Plaza yesterday. By rolling this religiously around the jaws and neck for ten minutes every day, the face will supposedly become slimmer and dreaded double chins will be prevented from appearing. I have a friend in Taiwan who swears by this and indeed she has a very slim jawline.
According to the instructions, the roller is supposed to be rolled up and down the jawlines. However, I would suggest rolling it upwards only as rolling it downwards seems contrary to the objective of achieving firmer skin.