The Thread Lubrication Unit is a special BERNINA sewing accessory to help when sewing or embroidering with metallic or loosely twisted threads. The thread passes through a silicone lubricating fluid after coming off the spool, which improves its gliding properties and helps prevent threads from tearing or breaking in the eye of the needle. This can help ensure the success of your sewing projects when using difficult-to-work threads. TIP: using a special metallic embroidery needle will further im