The only thing rubber there, you cannot see and that's an o-ring around the bulb end of the liner, right where the wire enters it. Other than that, no rubber. There's a copper "strap" that the gun sheath slides into that's one side (positive right now) of the electrical. Come to think of it, is that strap supposed to be "tight" around the copper part of the sheath? It just slides in and out. Seems that would be a poor connection, no? I do know that Kirk was pretty frustrated when he tried to last fix it. Maybe he forgot to tighten it up? I haven't checked it, because I'm unfamiliar with that part of this welder. I've used it a good bit, but never done maintenance on it. I'll check it tomorrow and see if it needs to be tightened there. That might be just how it's designed. I don't know.