If I recall correctly, the Pullrite was developed around 1955. Installation is/was complicated by the need to alter the vehicle exhaust system and routing the electrical supply along the drawbar. Backing the trailer involved different dynamics due to the pivot point being closer to the rear axle. I think it was forum member L Adams who posted his preference for the Pullright over the Hensley, having towed with both. I suspect that the disparity between sales of fifth wheel hitches and travel trailer hitches resulted in the special order only sales.