Wide application: these twin needles function as good accessories for sewing machines, compatible with most kinds of sewing machines Delicate design: each double-needle fitted with 2 needles can be easily threaded 2 same or different decorative lines to simultaneously stitch in a straight or pattern way Easy to collect: these twin double needles come with a small plastic durable box which allows you to conveniently collect and store twin needles Durable material: these machine twin needles are made of stainless steel and plastic with good quality, they are durable and sturdy for a long lifetime Package: totally includes 12 pieces twin needles in 3 different sizes, 2.0/ 90, 3.0/ 90, 4.0/ 90, each size has 4 pieces; And the sizes are clearly marked on the blue area