O-ring for Parsons/Green tower?

My Nashville B-Bender has always been pretty quiet. No weird mechanical noises until today, when it started clunking. I removed the bender unit and discovered that the tower O-ring was torn. Anything special about these? Can I just get another one from the hardware store?

Hardware store...take the torn one with you to get the right size. While you are at it, check the pads on the brass stops. Most typical reason for clunking is loss or the break down of these leather pads.