I bought a big cone in a neutral color. I put it in the bobbin and top and had to get a magnifying glass to see the stitches. :lol: It's very strong to be so thin. I don't have to worry about getting a scant 1/4 seam in piecing using this. I found this about the thread:
Size 15 and 23 are ultra-lightweight threads typically used for sewing garments and as bobbin thread. It is stronger than comparable spun polyester and cotton threads.
These ultra-thin threads are Soft because they do not require bonding.