Nipple tubes can be used by men or women to increase the size of the nipples. The cylinders are used with a pump to create a vacuum over the nipple which will act to increase the size of the nipple.
The diameter refers to the size of the opening of the tube,
at the bottom or base. The more commonly used size are the 3/4" nipple tubes. Each nipple tube comes with a female connector screwed in at the top. You also need to purchase
or own a pump (the brass handpump) to use them.