Eraser holder and straight edge

I don't know about you but I have a hard time drawing a straight line and I have to erase a lot while drafting, This nifty gadget will solve all of your 4'' line drawing and erasing needs! This holds a standard poly eraser you can find at any school or hobby store. This design also has a fold out straight edge and a spacer that will hold the eraser up as it gets smaller after use.