What type of bags do you use for Def. Line?

The Crowther 2-man sled is excellent, it teaches the player a variety of skills including keeping your hands in, forearm, and staying square. It's 'old school' to be sure but, you'll love it.
We also use th pop ups which are good for a variety of pass rush and tackling drills.
and shields are great for unpadded practices when you're teaching get-offs etc.

I've seen coach after coach struggle after going to hands when they used to be successful with flippers...Sometimes it's better to go with what you know rather than go through a learning curve....