The Wolf Shoulder Rest Rubber Buffer is the part of the Shoulder Rest that grips the adjustable slide and prevents it from shifting out of the position you want it in.
The Rubber Buffer is a necessary part of the Wolf Shoulder Rest.
Every player is different, as is every instrument. It is as important that the position of the Shoulder Rest does not become disturbed whilst you are playing, as it is important that it is adjustable in the first place.
The Wolf Shoulder Rest Rubber Buffer is of the utmost importance to the Shoulder Rest.
It is Much More Convenient, (And Much Cheaper!) to have the ability to buy spare parts, rather than having to replace the whole Shoulder Rest in the unlikely event that your original Wolf Shoulder Rest Rubber Buffer should become loose, damaged, or be lost.