One needle with two eyes. You thread your machine for twin needles using two spools of thread, but when you thread the needle, there are two eyes. So one thread goes in the top eye, the other in the bottom eye. Go through the stitches you have on your machine to see the effect you will get! Perfect for "bulking" up your top stitiching without compromising and threading two threads through the same hold.Size 80/12, 5 per card.