Split rings are like tiny key rings. They are more secure than jump rings, because they can't be easily tugged open. Split ring pliers and split-ring tweezers make these very easy to use.
Gold fill (also called gold overlay or gold-filled) is made by using heat and pressure to apply a layer of karat gold to a base of less costly metal (usually brass). This produces a surface with karat gold. The minimum layer of karat gold must equal at least 1/20 of the total weight of the item.
What's the Difference between Gold Plate and Gold Fill?
Gold fill jewelry is easy to take care of, and lasts years longer than gold plated jewelry, because gold fill (usually stamped 12kt GF or 14kt GF) is 50 to 100,000 times thicker than normal gold plating, and 17 to 25,000 times thicker than heavy gold electroplate (sometimes stamped 14kt HGP). See illustration for more info.