... side seam,decorative seam etc BSL-3800 Series Single/double needle chainstitch sewing machine Feature:1.BSL-3800 is suitalbe for jeans side ... vibration.BSL-3810 1 needle, chainstitch sewing machineBSL-3820 Tendem 2 needle, two chainstitich sewing machineBSL-3830 Parallet 3 needle,.three chainstitch ... , 8, 9.5, 12.7mm options. BSL-3800 Series Single/double needle chainstitch sewing machine