Description: Made of aluminum alloy material, corrosion-resistant and durable. Lightweight and high strength, It allows to expand your underwater photo video gear to your demands. Ball arm is used as a bridge to connect underwater tray/handle to underwater strobe/video light. Great accessories for underwater diving photography lovers. Specification: Materials: Aluminum Alloy Ball Diameter: Approx. 2.54m/ 1 inch Total Length: Approx. 9cm/ 3.5inch Package Includes: 1 Piece Ball Arm Adapter