THESE ARE VERY SMALL!!! 4.5mm spring rings are about as small as any jewelry comes with.LISTED with 6mm Spring Ring item 153711294615 Double 4.5mm spring rings come on item 153308240226 & 6mm on 265158506468. This clasp is: 4.5mm diameter X 15mm, 4.5mm Spring Ring clasp 3/16" X 5/8" these add 1/2" to any item a dime coin is 17.5mm In our opinion, suitable for chains up to 25grams. You be the judge for yourself. No hassle returns. It is strong enough to hold one side & slide all around the Nickel without it even starting to come apart. Spring ring and other clasps WILL be slightly attracted to the magnet, as their internal springs are steel. Rest assured these are solid 14k NOT responsible for any damage or losses due to clasp failure. USE AT YOUR OWN RISK if you use a PACEMAKER, INSULIN PUMP, OR DEFIBRILLATOR etc...Thanks Weight: 0.62grams each 14k White Gold are listed, item # 153394915373 & Rhodium Plated 153411261947. NO RETURNS ON International