These bobbins are sold in a box of 144 pre-wounds. They are white 60wt polyester thread on class 15 plastic bobbins. When the bobbin is empty, it is reusable and you may wind any bobbin thread onto it.
Class 15 bobbins fit a number of different domestic sewing machines. Janome machines use the class 15 bobbin.
There is a separate listing for class L pre-wound bobbins if your machine does not use Class15. We do highly recommend using the correct size bobbin for your machine for best results.
These bobbins are also available in smaller packs of 24x for $15.00. Please see separate listing for this.