Clover 490/NV - Hera Marker
The Hera Marker marks whilst simultaneously making a crease. It leaves no residue on the fabric. Markings can be seen on both the front and the back of the fabric.
This tool is ideal for marking your quilt. You can use a quilting ruler or draw lines free-hand. Even though this tool isn't making actual marks, you can still use it like a pencil.