I saw the Taly Golf training aid originally over at the LynnBlakeGolf.com Web site, but didn't know what to think of it. Here's a sample video on how it works.
From studying this training aid a bit more, I think it is a solid training aid. Mainly because it is teaching the golfer 'left side connection' without really mentioning it that way. If you look at the swing, the red ball cannot move like it's supposed to unless there's that upper left arm 'connecting' to the upper left chest right by the left nipple.
And the key to the Taly is to hit the ball 'without swinging your arms.' That's a 'pivot controlled hands' motion where the pivot moves first and the hands follow. I recommend the 'pivot controlled hands' motion because I find that is the motion that most golfers have success with. There's also the 'hands controlled pivot' action where the hands go directly downward in the downswing first and then the pivot follows, but I find that not only myself but many other golfers struggle executing that move.
The only criticism I have of the Taly is that I believe that most golfers would be well off doing a 'left side connection' drill and just taking a golf glove or a nerf ball and sticking it up high on the left armpit and not letting it fall out during the swing (up until the halfway point of the follow through). They could do a lot of 9-3 golf swing drills and work it out just fine. And like I said, there are some golfers who are better off using a hands controlled pivot motion than the pivot controlled hands motion that the Taly promotes.
However, the Taly may work great for you instead of using a left side connection drill. They can be found at www.talygolf.com for $70.