What should I do?

My sister is very fat. Her birthday will be come. I want to choose a gift for her. Such as clothes. But my friend told me that clothes is so ordinary. To choose some slimming product for her maybe more suitable. What do you think? Have you used slimming massage belt, how do you feel its effect? this one , dual channel vibration fitness belt.(http://www.elijahstore.com/ab-tronic-x2-dual-channel-vibration-fitness-belt.html) How do you feel?