I have been using these catheters for nearly 8 years. At first it was too slippery to use until I understood the instructions which includes knowing the upside and downside. The green top has enough friction to guide and push the catheter without having to touch the part that is inserted. These catheters are less messy than my old style that required a lubricant. It also reduces the chances of getting a UTI from bacteria entering the urethra and beyond