Thirty strands of silvery tube beads are strung in three sets of ten draping beautifully from lacy silver tone end caps.  The round box clasp is decorated with a tight swirl of the same silvery beads giving a finished look to the back of the neckline.  The total length varies from the shortest of 17" to 20".  They are marked on the back of the clasp "Japan" and are of the 1950s vintage.

 

View of the clasp: