Lock stitch needles come in various sizes and types, each tailored to specific sewing tasks. The most common size system used is the metric system, which ranges from 60/8 (very fine) to 110/18 (very heavy). Selecting the right needle size is particularly important, as it can affect not only the quality of the stitches but also the overall outcome of the sewing project. A needle that is too large can create large holes in delicate fabrics, while a needle that is too small may struggle to penetrate thicker materials, ultimately causing skipped stitches or a broken needle.