SiRUBA HSO-747D Overlock Sewing Machine for professional finish, with 2 Needle-4 Thread, versatile stitches, color coded threading guide, and micro safety switch 2 Needles and convertible 3 or 4 thread Free-arm sewing, convertible presser foot, and differential feed mechanism, and light for a brighter work area Color-coded threading chart for fast and easy threading Differential feed prevents wavy seams in knitted fabrics and movement between the layers of fabric. It also ensures pucker-free seams on light weight fabrics A machine adjustment chart to help you to sew beautifully based on stiffness and thickness of fabric, thread size and type.