Standard is 16 inches, they will add up to 2 inches complimentary. If you have a good sa, you can get 3 inches.
You can request the jump link, but they may charge. They do not do them for regular pendants, only Magic and diamond pieces.
Thank you sjunky for your input. It is only for the plain YG vintage pendant so they will just add up the links I assume. If I can't wear it in16 inches after the 2 inches lengthened then I guess I will leave it as it is. I don't know it is just me but when I wear my vintage pendant in 14 inches it doesn't look flattered on me so no use of the existed jump ring it comes with originally. [emoji29]