They are one in the same. In the model number of a Uhing drive assembly the slowdown cam is designated as “V.” The V-cam is a device which reduces the linear speed of a Uhing model RG drive at the reversal points. If the drive is moving faster than 0.25 meters per second (9.8 inches per second) then the V-cam is needed in order to assure that the automatic reversal lever functions properly.