21347 is a height adjustable distance rod, fits to speaker hat at one end, M20 bolt at other.
Steel tube combination to connect satellite systems. With bottom M20 thread to attach connector plate 24116.
Zero backlash and absolute vertical position.
Height-adjustable by locking screw and safety-pin.
Not quite the right size? You can also check out 21337 (includes M20 one end, and 35mm at the other)