â—† 2-Needle, 2/3/4-Thread Overlock Machine with Dial Type Thread Tension Slots â—† 2-Thread converter is optional. â—† All the Popular Overlock Stitch Variations: This 4-thread overlock with differential feed and automatic rolled hemming was designed with economy and performance in mind to sew all the popular overlock stitch variations. â—† 4-Thread Overlock. â—† 3-Thread Rolled Hem. â—† Differential Feed: is easily controlled and adjusted by a dial located on the exterior, left hand side of the machine.Materials that stretch easily such as knit fabrics can be finished beautifully using shirring stitch. Materials that are likely to cause stitch gathering can be finished beautifully using stretching stitch. â—† Foot Pressure: can be adjusted according to the fabric. Adjusting the pressure to lightweight, medium weight or heavy weight fabrics allows you to sew beautifully. â—† Color-Coded Threading Guides: throughout the machine make threading easy and efficient. â—† Adjust Stitch Length: by simply turning the knob located inside the machine within the range of 1 to 4 mm.