Are these for tubes? What specific plastic are these designed for?

 

From the Arkie website:

 

From Swim Baits to Tubes and Trick Worms, a true Multi-use Head. Designed with the weight forward, so that actions such as "Walking the Dog" can be done with fluke style baits. Super Sharp wide gap 4/0 hooks in both red and black nickel compliment the hooking power of these in larger soft plastic bodies.

So I'm supposed to slide that big lead section through the head of my worm/fluke/swimbait when I'm doing a weedless texas rig?

50 minutes ago, wasabi_VA said:

So I'm supposed to slide that big lead section through the head of my worm/fluke/swimbait when I'm doing a weedless texas rig?

No, you push the eye and bent section into the head, then the hook in like a normal T-Rig...the lead sits below the head.