I have the lock-on too, tubular aluminum, and would buy another one if they were still made. I bought mine the first year they came out, 1983 I think. The original binders were bad, and were replaced with better ones. The first year they had no brace from the ladder to the tree, but one was added the next year. I don't know how long they were on the market, but I think maybe they were too lightly built for magnum-sized hunters. Mine weighs only 20#. Right now it's set up in a prime funnel up in MO, waiting for me and the rut.