This is an indispensable and handy tool for anyone who sews with a sewing machine. Use it to position your machine's needle exactly where you need it as well as to check the accuracy of your needle's position. You can position your needle perfectly for a scant 1/4", 3/8", 1/2", 5/8" or 3/4" seam. It has a ruler with markings to 1/8" and the 45-degree end is very useful when piecing your binding strips together.
To use the seam guide, simply place it under your machine's foot so that the ruler side edge of the guide is aligned with the right edge of the foot. Adjust your needle so that when the needle is lowered, it goes through the hole for the seam size that you want.