This piece attaches to the shoulder rest with a nut and holds the drum into which the feet are screwed. The Original rests (4/4violin, 1/2-3/4 violin, viola) and Collapsible models feature two of these pieces which are slightly different and are not interchangeable. The bracket for the narrow end of the shoulder rest is higher than the bracket for the lower end. Their shapes are also slightly different. Brackets for Original and Collapsible rests are supplied with drums.