The diameter of the camera rod is industrial 15mm standard. Durable:Made of 6061 aluminum alloy, well finished and precise CNC processing, This camera rails rods can survive exposure to weather, moisture, and frequent handling thanks to the anodized oxidation coating. Compatibility: This 15mm aluminum rod clamp combination is perfect for camera riser system and movie making accessories, rod support system, handle grip, matte box, magic arm, monitor, battery pack, battery adapter, lens support, follow focus mounted on the rod. M12 Inner Thread: M12 inner thread on each end of a rod, so that you can use M12 threaded connector to lengthen the rod use M12 rod end cap to prevent your accessories sliding from rods.