Thread wound is a spiral thread decorative technique on glass vessels, made by winding a glass thread repeatedly around the vessel at a late stage to avoid melting the thread flush with the surface. Another spiral thread technique, embedded thread, involves applying a thread earlier in the process so it melts flush with the vessel surface. Thread wound is similar to spiral coil, but spiral coil usually refers to a thicker trail, rather than a thinner thread, and spiral coil is most often applied only to the neck. Vessels were thread wound both in the East and West. Thin threads were popular in the first and fifth through seventh centuries. In the first century the thread was usually opaque white, sometimes blue, and was wound around the neck and body. This style was revived in the late second and third centuries. In the late fourth and fifth centuries but the thread was often applied only to the neck (similar to spiral coil) and the thread was usually the same color as the vessel or translucent blue. In the sixth and seventh centuries Byzantine glass bottles and threads were often thread wound only on the upper part of the neck, near the mouth.