Curious if anyone has any feedback on those? Looks interesting.
I would recommend the Whip-Hit (if that's the rope bat you are meaning). DD occasionally works with the coach who help create the Whip-Hit version (think there are other rope bats out there too) and he turned us on to this. It is a fantastic tool for hand/barrel path training, and we found it to work well for extension too. At $80 it's a little pricey, but worth the investment. You can make something very similar with a bat handle and ball much cheaper, but this comes with a secure handle and nice "professionally made" feel. It's especially effective when hitting front toss. It takes some practice just to hit off a tee with it and when they hit a ball in flight they definitely have to have proper path/extension. The Whip-Hit is designed where the ball is at the approximate sweet spot of a 33" bat. Word of caution...use batting helmet when getting used to it. DD and both whacked ourselves on the head when first trying it. Like with any training tool though, it's best used for a specific purpose. We did find that she started to bar out her front arm to cheat the tool a bit after using it for a while. Worked best to switch between whip-hit and regular bat about every 10-15 balls when working specifically on path.