With regular use and grinding, all rolls wear down. Shallower grooves (approximately 0.070") don't channel off water as effectively, which slows your production. When this happens, the roll is typically ground to remove that 0.070", and new grooves are recut — a waste of 0.070" of good roll cover.
With the PRG process, however, the grooves on any type of rubber or polyurethane rolls are deepened to the original 0.120" depth, which restores water removal efficiency, saves material and saves on future maintenance costs.