The Prym bobbin box offers 12 CB bobbins in an easy-to-store box. Bobbin size: diameter 20.5mm, height 11.7mm. Bobbins are an integral element in the sewing machine. With a bobbin the threads are knotted and they therefore determine the quality of the seam. The plastic box is available with 12 metal or 12 plastic bobbins. As the box is transparent, you can easily spot the thread colors and always get a good overview of the remaining thread amounts.