This sterling silver necklace is from a company called TJ and Co. They also make picture jewelry and things for dads as well as brides and grooms. It's a sterling silver ball chain necklace and three discs with each kids name. You can also get them in gold. Their website is www.tjandco.com. Stella and Dot also does something similiar with initals I think and you can find them at www.stelladot.com.
This my husband had made for me the first christmas after I had the twins. On the gold bar are the three birthstones. Garnet for AGB and peridot for the twins, CMB and OPB. The kids call it my "family key" necklace. I can't refer you to a web site since Hubby worked with a local jewelry designer who has also made my wedding ring. This one is my favorite!