The 4" & 4.5" Gorilla Tube molds are just like Do It's other tube molds, they make awesome baits.
This is a great bed bait, flipping bait, jig trailer, Carolina rig, T-Rig, etc. If you haven't fished a tube before this is a great one to start with as it has lots of movement and is very productive using it the same way you would a creature bait.
Here's a fishing tip that works great on most tube baits (T-Rig or C-Rig): plug the opening of the tube with a small piece of worm and hold it in place with a toothpick. This will trap the air in the tube and cause it to float off the bottom. Make sure you don't lay your rod down - you very well could loose it!!!
There are multiple lengths of tube inserts available so you can customize the thickness of the head. The 4" mold uses any tube insert size up to a 2.0" insert. The 4.5" mold uses any tube insert size up to a 2.25" insert.
Be sure to add a touch of softener or worm oil to the insert and tube insert so the finished tube slides right off.