This is my rods. You can see how corrugated they are. If you run your finger nail down them they really make a noise.
Looks like every Rev rod ever.
Seems like people who fly a LOT, like iQuad did, get sail damage from stretching over many hundreds of hours of flight time so the Pro Revs add reinforcement to keep the sail from stretching. Most of my Revs are over 15 years old and even though the've not been flown nearly as much as some, wear from the vertical spars and/or stretching isn't a problem.