I finally came across these Boys Surfer Shark Tooth Necklaces made with Heishi wooden beads plus a sterling silver shark tooth charm, lobster claw clasp, and extender. These are made and sold by the Etsy shop owner of Butterfly Gem and sell for $17 each plus shipping. The owner Alicia was very nice to deal with and she helped me figure out what sizes I needed for each boy. The extenders make these necklaces adjustable and should last for quite a few years if my sons take good care of them.
We ended up giving these necklaces to both our boys in January for their birthdays. Our 3yr old was thrilled to have the same necklace as his big brother.