Not intended to support a case with a 100mm macro lens plus a flash ...

Only the lower part is interesting because with its limited displacement 3cm, and order directly on the threaded rod, she is the only one with a sweet move. The upper part with its angle transmission control for advancement, has more play, and there is a cantilever important when the casing is fixed to the plate. The upper control then has hard points, all this in front worsen during frequent use ... Point the positive thread adapters.