Push forward for a seam ripper that cuts threads on seams. When closed use as a thread cutter for sewing. The retractable safety feature allows this tool to be used both as a seam ripper and a thread cutter when closed. Details: 0.75" x 4.25" approximate size To use as a ripper, slide button forward and fix To use as a thread cutter, slide button back and use with blade tip stored Do not apply excessive force to blade tip