I have owned a Sidewinder ever since they first came out. I have used it a lot and I love it. It runs with either batteries or a cord, but I never use the cord as it just gets in the way. It is well-made, stays in one place, and winds the bobbins better than any sewing machine bobbin winder I have ever had. The batteries last a long time and seldom need changing. Maybe I just got a good one, or maybe they have changed them over the years, but should mine ever need replacing, I'd do so in an instant.