It was such a pain for me to cut it and try to get it even so it would fit around the bobbins right . I got the 1/2 inch.I had to keep trimming so it would fit inbetween the top and bottom of the bobbim. but then again I have trouble seeing out of one eye so that threw things off too. Then the bobbins were still loose.
I wanted something that kept them all in one place and was cheap and easy. This fit the bill for me.