Extenders are used to allow the finished item to have a variable length -- usually anywhere from two to six inches. They come in a variety of lengths and styles. They are usually finished with a jump ring at one end and something decorative at the other -- a stardust bead, puffed heart, etc. The end with the jump ring is the one you would use to connect the extender to your piece. The other end of your finished piece should have a clasp of some type -- lobster, trigger or spring ring. The clasp can then be attached anywhere along the length of the extender for varying lengths.