Juki TL2010Q 9" Arm High Speed Professional Straight Stitch and Free Motion Machine with AccuQuilt Stitch Regulation

Sub Tension Unit Even if strongly twisted thread should be used, the unit will avoid "return of twist of thread" and supply needle thread to the main tension unit without thread quivering. It helps sewers create sttiches with stable thread tension. The improved thread tension system intelligently avoids the return of twisted threads, even when using strongly twisted thread, giving you a more stable stitch tension and eliminating "thread quivering".