SINGER 14T967DC-WORKBOOK QUANTUMLOCK - Manual (Page 98)

Three-Thread Ultra-Stretch Mock Safety Stitch
This stitch stretches with the fabric, the seam will not break when the fabric is
stretched. It is ideal for super-stretch knits like those used on swimwear or athlete
clothing. This stitch uses two needles and one looper.
Left Overedge Needle Thread
Lower Looper Thread
Right Overedge
Needle Thread
Three-Thread Ultra-Stretch Mock Safety Stitch page 1