... widely used for side seam,decorative seam etc BSL-3800 Series Single/double needle chainstitch sewing ... shirts, trousers suture your sleeves,etc .2.BSL-3800 also can provide high efficiency and stability ... with low noise and vibration.BSL-3810 1 needle, chainstitch sewing machineBSL-3820 Tendem ... 4, 4.8, 5.6, 6.4, 8, 9.5, 12.7mm options. BSL-3800 Series Single/double needle ...