I never thought that I would use prewound bobbins, I changed my mind, when I got my big embroidery machine, it came with several, I can get them cheap, in bulk in white, I usually use them for emboidery, I did find them in color once but the store since went into retirement. I have left the cardboard on and taken it off, the sensors work better with it off. As it is compressed the thread doesn't unravel on them when you do this. They do have more thread on them. I have not used prewound withthe long arm yet, they are harder to find and I have to go to yet another store for them. It came with a bobbin winder that is really fast though as well so I wind my own to match color better.