Reverse Stop & Lock Knob for Ultrafeed Video Demo shows the benefits of the Reverse Stop & Lock Knob. Using this feature makes it easy to get precise stitch lengths in forward and reverse. Simply tighten the Lock Knob to the desired forward stitch length and set the reverse stitch by moving the Reverse Stop to the desired length. This video also demonstrates how to add a spring to a stitch length lever. Adding spring to this lever makes backstitching fast, however it is not recommended for sewers who do significant sewing in reverse.