Squaring Template Set
This template set comes with 6 different sized squares that will make a finished size square in 1”, 1-1/2”, 2”, 2-1/2”, 3” and 4”. These can be used to make and square blocks like quarter square triangles and hour glass blocks.
My favorite use for these is to make half square triangles with my method of sewing two strips right sides together with a 1/4" seam down both sides then placing the center diagonal line on the ruler directly over the seam and cutting around the 2 sides of the square. This leaves a perfectly square half square triangle and does not waste a lot of fabric.
There is a tutorial on my YouTube channel showing this method.