They are industrial standard 15mm rods for 15mm rod systems.
15mm rod connectors are included. It allows you to connect the 15mm rods together.
Material: Aluminum Alloy Color: Black
Both 2 pair of 15mm rods has inner M12 thread on each end of the rods.
Includes one pair of 15mm rods 8 inches long and one pair of 15mm rods 12inches long.