A hydrophilic catheter is an intermittent catheter coated with polymer that becomes slick when submersed in water. The polymer runs the length of the tube and remains intact through the insertion process reducing pain and potential injury to urethral tissue. Most hydrophilic catheters are either prepackaged with sterile water or come with a sterile water pouch built into the packaging that the user breaks before catheterization. Many experts believe hydrophilic catheters are more sterile as they do not require manual lubrication and are therefore less likely to cause infection.