As I found out, but then 20-years ago, all we operated was the Heisler, and it uses soft grease. We actually bought one from Bob, a screw type, which was barely satisfactory, and found a lever action one last year, it kept breaking, but have machined another head for it. The air powered one is mostly for the sake of our volunteer crew members, who have a problem with properly placing the grease. Go figure!! Ron