Due to the consistent nature of hydraulic pressure created by the Bathmate range of pumps, the users penis will increase in girth a lot quicker than it will in length. This is because the surface area is greater around the girth of the penis than the length. This will result in the penis touching the sides of the pump, meaning the hydraulic pressure will not be able to expand the girth of the penis further. When this occurs, the user would naturally progress to using an X40, however many X40 users have commented that the additional room for length expansion is not required as they haven't out grown the length of the X30 or Hercules. The Science: In order to obtain maximum hydraulic pressure, it is important that the correct size pump is used. We always advise our customers to purchase a smaller pump (provided your penis fits comfortably in it) as this will result in the optimum hydraulic pressure around the penis. Using a pump that is too big will result in lower pressure around the penis meaning slower or no growth. Here lies the demand for the X30 Wide Boy. The Wide Boy has a wider vessel but no increase in length on the X30 meaning that optimum hydraulic pressure is maintained, resulting in quicker growth.