The polyurethane disc is backed up by two metal compression straps, one on either side of the flexible coupling. These metal straps hold the system in constant compression whether the drivetrain is in forward or reverse. This feature extends the life of the system dramatically.
The R & D Flexible Coupling will also absorb shockloads resulting from gear changes, or the propeller striking a submerged object. The polyurethane disk will distort with light shock loads and is designed to be sacrificial in the event of severe shock load, saving on expensive drivetrain repairs. If the disc is destroyed from massive shockload the metal compression straps keep the coupling intact ensuring that the drive system is functional in both forward and reverse.