3 Thread Overlock for single layers. 4 Thread Seams for two layers. 2-Thread Adaptor Optional for fine roll hems. Easiest Built-In Rolled Hem slide lever on needle plate. No need to change needle plate for roll hem set up. Differential Feed to Gather or Straighten Fabrics. Disengageable Knife Cutter Mechanism. Most Reliable Serger Brand on the Market. Like Bernina 700D also make by JukiJuki Home Serger Comparison Chart.