The CS-15 iris rods are fabricated from high grade precision aluminum with a hardened PTFE anodized black finish. The PTFE finish reduces the wear and improves adjustment settings.This iris rod features 3/8" female thread on both ends. In combination with the CS-155 (sold separately) these rods can be extended in length. The memory slot can be used to indicate the user preset rotation angle of the CS-151 clamp (sold separately). This reduces the setup time of the rig.