This jump ring worked well for me to replace "bails" on two heirloom silver charms.
Siliver Jump Rings (.9 x 3.9mm) 19 Gauge
This size is approx. 4mm or .25 inches, The gauge is 19. It is the size I use most often.
I prefer a slightly stronger gauge, but this was all that was not sold out in this size at the time.
(It does fine for delicate earrings with just one tiny bead; no weight to support.)
I like this size jumpring for more delicate pieces so that they don't overpower. These worked very well for attaching the crucifix to the bracelet. It is small but strong. I use a lot of sizes and guages from artbeads and have always been happy with them.