Walter Lampl Vintage 12k Gold Serpentine Choker Necklace

The necklace is marked 1/20 12k g.f. and bears the hallmark of Walter Lampl - WL within his "shield". This fantastic gold filled necklace measures approximately 15" x 5/16". It has a little stretch in it also. It has a unique concealed clasp. It is in excellent vintage condition with some patina near the clasp. It probably needs a proper cleaning. Vintage from the 1940s - I found an ad dated May 1947 in "The Jewelers' Circular-Keystone highlighting this piece. Walter Lampl, of 5th Avenue NY jewelry company, made jewelry from 1921 to 1959 and his slogan was “Creators of the Unusual as Usual”. This is a rare piece and very cool! Questions welcome. From a smoke free home.