The plastic warping spools are used when sectional warping. They can hold up to 8 oz. of yarn, depending on the density. You will need one spool per thread in each section and a spool or bobbin rack to hold them during the warping process. This spool fits on many hand-operated single-ended bobbin winders. However, the sheer number of yards to be wound for a project makes an electric double-ended bobbin winder very useful.
Dimensions: 2 3/4" in diameter; 4" long. Shaft opening is 5/16".