Blackberry

I have never seen spools of thread this large before. These came from an estate sale. I got 4 spools of which the two largest ones are white for about $1.50 each. I also got some embroidery thread for tying quilts and a ruler that I do not even know how to use. I am hoping I can use this thread in my sewing machine without any trouble. I think these large spools are usually for sergers.