Aluminum alloy material, sturdy and durable, can maintain stability in harsh environments, and will not age or break like plastic products. Flexible knob for easy tightening. This is long arm with total length of 5.9"(15cm). You can choose different lengths according to your needs. Compatible with RAM mounts and other all industry standard 1 inch(25 mm) B size ball components. What you see is what you get - we promise that all photos and videos are real product photos, so you can feel the real texture and get the product in the advertisement. This is a long size arm, with total length of 5.9in(15cm) and net weight of 178g. It is made of aluminum alloy, sturdy and durable, and will not break like plastic products if used for a long time. The middle knob can easily tighten the arm. Compatible with RAM mounts and other all industry standard 1 inch(25 mm) B size ball components. High quality product is a good choice for you to install the mount on motorcycles, cars, bicycles, and ships.