- 4423 Heavy Duty Sewing Machine - 23 Built-in Stitches basic, stretch, decorative - 250051596 Heavy Duty Extension Table for Mechanical HD Machines - Create professional results easily Singer Heavy Duty Sewing Machine - More Powerful Motor for extra high sewing speed - 23 Built-in Stitches basic, stretch, decorative - One-Step Buttonhole for consistent results every time - Heavy Duty Metal Frame for long lasting durability Singer Heavy Duty Extension Table for Mechanical HD Machines - Create professional results easily - Gives extra stability / support when sewing larger projects - Easily snaps onto the free arm of the machine - Legs easily fold away for storage