Okay, so a casing cutter is a tool that helps people cut through the outside of something called a casing. A casing is kind of like a cover or a shell that goes around things like sausages, cables, or pipes to protect them or hold them together.
So imagine you have a sausage with a tough cover or casing around it. If you want to cook or eat the sausage without the casing, you need to cut through it. But because the casing is tough, you can't just use regular scissors or a knife. That's where a casing cutter comes in.
A casing cutter is like a special pair of scissors that has a sharp wheel on one end instead of a blade. You place the casing cutter over the sausage so the wheel is touching the casing. Then, you turn the handle that's connected to the wheel, and the wheel spins around, cutting through the casing.
After you've cut through the casing, you can peel it off and cook or eat the sausage inside. People who make sausages or work with cables and pipes often use casing cutters to make their work easier and more efficient.