This template is something left from my years in graphic design and I only recently started using it for seam building and now it is my favorite tool . I just love the flexibility it gives me... Now these templates are not cheap and this one is available for $29 at Amazon but I see them on Ebay for as cheap as $7... This particular one is R-77 Berol eljpse master and is about 6x9"
My most recent discovery was quite by accident. I was going through a bag of craft stuff from the thrift store...and notice "plastic canvas" sheets in several sizes.... One of them had a grid exactly the same as the grid of the graph paper in my seam book... So I cut off a narrow strip and now I whatever I plot out in my seam book I can reproduce exactly.