By pump the vacuum wine stopper suck the air out of the bottle several times until it sucks itself tighty.Then will help preserve wine flavor for about 7 days, The wine stoppers built in vacuum value and is made of ABS & Food Grade Silicone,it's safe to human body, non- toxic, high-class wine accessory. The vacuum wine stoppers's size is 2.75"*1.77",it's good for traveling and present as a gift for Christmas,Brithday etc, The stopper is made of food grade silicone, which can make the wine not leak.