Gold Filled 14/20, 14/20GF, 1/20th 14K and 14KGF are all legal, US Federal Trade Commission quality marks that may be affixed to finished 14K Gold Filled. This product is made by bonding, through heat and pressure, a solid sheet of 14K Gold to a base metal. The thickness of the sheet of gold depends on the weight of the item. Basically, the heavier the item, the thicker the sheet of 14K gold and always equal to 5%.