Some toilets come with a rigid water supply line - meaning it cannot be bent or twisted without damaging or breaking. If your water supply line is not flexible, you will need to purchase a flexible hose line (seen in the image below).
To ensure a good fit, measure the length of your current supply line and add 4 inches. We recommend visiting your local hardware store; and here is a range of Omigo approved supply lines we like on Amazon: Water Supply Lines