Lens Tubes are acrylic with a knurl grip and black paint. The capture ring above the element easily removes for element replacement. Foam on the inside. The thread system is different from Ports as once the Lens Tube attaches, it can spin in either direction and stay on. The foam on the inside grabs the zoom control and allows for smooth zoom.Lens Tube - LT-Z for Canon 24-70mm f2.8