Georg Jensen Sterling Silver Super Rare "Chime" Adjustable Necklace No. 120A by Astrid Fog.
This unique, sterling silver necklace has a horizontal segment that slides up and down so that you can adjust the chimes.
Measures 24 1/2" from back of neck to end of dangles. Measures 14" from back of neck to top of pendant.
A similar example of the design can be found on p. 295 in the book, "Georg Jensen Jewelry" edited by David A. Taylor.