UPDATE:  This 2012 post has been updated to reflect the existence of two different Sta-Bar Kits.

Two different manufactures (were there any others?) offered stabilizing kits that were meant to reduce some of the horizontal shifting that can occur when using a rear lift.

Here’s a detail look at a Monroe 3pt Hitch without a stabilizer hit.

The Roper Manufacturing Company out of Zanesville, Ohio, manufactured a set of bars that pivoted on special vertical plates attached to the ends of the PTO bar and attached to the lower links as highlighted below:

Here’s the Roper Sta-Bar Kit brochure:

The Green Manufacturing Company’s Green Star-Bar Kit has bars that appear to attach to the outside of the lower links in a similar manner to the Roper kit. I can’t tell how the kit attaches to the PTO bar or how that might differ from the Roper setup. The pricing shows it was slightly less expensive than the Roper Sta-Bar Kit.