Size: The "8mm" measurement refers to the diameter of the jump ring, meaning it is 8 millimeters across when measured from one outer edge to the opposite outer edge.
Thickness: The "1mm" measurement refers to the thickness or gauge of the jump ring, meaning it is 1 millimeter thick.
Gold Filled: As with the previous explanation, "Gold Filled" indicates a layer of gold bonded to a base metal (usually brass) through a process involving heat and pressure. This creates a more durable and longer-lasting finish compared to traditional gold plating.