The Thread-lubrication unit is a help when sewing with metallic or loosely twisted threads. After coming off the spool, the thread passes through a special silicone fluid which noticeably improves its gliding properties. This allows reliable guiding, and effectively prevents challenging threads from tearing or breaking in the eye of the needle. It also helps ensure the success of ambitious sewing projects using difficult-to-work with threads. TIP: using a special metallic embroidery needle will further improve your sewing or embroidery results with such threads.