What is a double-needle used for in sewing?

A double-needle is specifically designed to create two parallel rows of stitching on the top layer of fabric, which adds both function and decorative elements to garment construction and finishing touches. This type of needle works by using two needles attached to a single shaft, allowing for synchronized stitching that enhances visual appeal and provides a professional finish.

When using a double-needle, the sewist can achieve a finished effect that is commonly seen in hems, decorative topstitching, and on knit fabrics, where the elasticity of the stitches is beneficial. This capability sets it apart from other sewing tools designed for various functions, emphasizing its role in enhancing the aesthetic and structural integrity of sewn items.

The other options reflect various sewing techniques and tools but do not accurately capture the primary function of a double-needle, which is to achieve parallel rows of stitching.