A rainbow sky sewing, 20 spools of thread in bright colors, as varied as the picture accompanying the description. Tensile strength, but not yet used machine. From black to white through navy blue, gray, three shades of green. No color and no double brown, but there is none in the rainbow sky .. Having noticed a difference in thickness between the coils, the clearest being larger, I have weighed, and light colors make 17 gr. and 13-14gr dark. According to the description, the coils are 25x55mm and weighs 358gr. Well, those that are more heavy, light, they are 27 mm thick. My concern accuracy always pushes me to check. The quality it is, bright colors, what sew clothes, regardless of the color until 9.160 meters. A very good deal.