Cannot identify maker of piece

by Robert
(Lawrenceville, NJ, USA)

What is the item?

18k yellow gold link bracelet with diamond stations and leaf design with hand engraving look on links.

Can you please provide all background information?
Purchased from an estate.

What are the markings?
Webster
SW (crown symbol) 750 (shield symbol?) a (plus sign with 2 at 12 o clock and 0 at 3 6 and 9 oclock.)

Where are the markings?
On the female end of the clasp