Zacuto Z-RE-FM4.5 4.5-inch Male and Female aluminum rod has been discontinued, here are some related products you might like:
Zacuto 4.5" aluminum rod for DSLR and video rigs. Male on one end, Female on the other. (1 rod only)
Zacuto's rods are all lightweight; 15mm diameter with 60mm spacing and clear anodizing. They are made out of 6061 aluminum and the threads are ½” 13.
More information about Zacuto Products (Link to Zacuto Website)