It is just a Styrofoam block, not branded with a name.. There are times I have to lay the block on it's side stand on top of it, grasp the arrow with Danny's puller with one hand and the lower shaft with the other and pull with all my might.. Once it "breaks" it comes out easy.. The silicone spray allows me to pull it out without standing on it, but still requires effort...
A trick I seen Don use was to spray the actual target with the silicone spray, that helped quite a bit too, don't know what kind of target is under the duct tape though. I have had no experience with the 18-1 yet.