There are four parts to this design. Two are the lid and main body of the case. These join together using a simple hinge system to create a case which can be closed and then secured by sliding the ruler on top which locks it shut and provides storage for the ruler. The ruler is a full 30 cm with cm increments and easy to use indents for marking out while the other side was left flat for creating straight lines. The major feature of the ruler is the end comes off with a pencil attached. This allows for a pencil which can be quickly accessed without opening the entire case. The pencil is secured in the ruler using the pencil topper which will prevent the pencil from sliding out during transit and stop it from getting stuck within the ruler.