Is...the Blue Ox Sway-Pro! By far the best I think and it saved my butt when I had a blowout last Labor Day Weekend coming back from Port Aransas (Corpus Christi TX). About half way between Corpus and San Antonio we suffered a blow out. The tire lost pressure due to the rim and the tire shredded to bits in a nano second at 70+ mph. Although the tire dropped like a rock onto the rim, I never lost control and the trailer tracked straight and true without the slightest bit of sway! We were able to pull off I-37 to the shoulder with no problem. Now besides this, the Sway- Pro is SOOOO easy to hook and unhook and can be done in a matter of seconds. Add to this the selection of different spring bars that are simply interchangeable and a receiver that can be adjusted to the proper level, plus the rotating latches that are very easy to work...and you have a winner. Check the Blue ox out on youtube....
Remember, you get what you pay for!
I installed mine myself and it was very easy as well. you just need a few tools and a level surface and 45 minutes. That's it!
Tom