Janome has packaged these little gadgets together to help your ruler work. Both help to make sure your ruler work designs have thickness in mind. The stitch line disc recreates the sewing experience you have when designing design patterns on paper, while the gauge is very helpful for measuring those 1/8, 1/4, 1/2 and 1 spaces when you are actually sewing! Youll be surprised how these small, but mighty items come in handy!