The Dritz Better Bobbin Winder fills bobbins evenly and fully from regular AND large spools of thread. Included is a special thread guide for filling bobbins with large spools of thread. This machine can fill bobbins completely, fill bobbin partially, fill bobbin from thread already in machine: no unthreading required, a built-in tension disk. The easy to follow thread guide fills most bobbins: plastic and metal. It"s compact size makes it great for your sewing table or your travel tote and the removable cover stores conveniently under the winder. Complete, detailed instructions are included. This handy little tool uses 2 AA batteries (sold separately) or the included UL approved power adaptor. Winder measures 3-Inch x 5-1/2-Inch x 4-1/4-Inch . Winder features a 1 year limited manufacturers warranty.