This double ball screw is made of high quality aluminum, sturdy and durable. This double ball mount is 25.4mm (1") to 25.4mm (1") ball head, compatible with 25.4mm to 25.4mm base arms. The length of this ball adapter is 2.5 inches from one end to the other, it is used for GPS extension This 1" to 1" double ball mount can be used for Garmin GPS mount and bike mount and other standard 1" / 25.4mm / RAM B socket mounts. With this double ball mount kit, you can rotate your game GPS, camera mount or phone holder 360°, it is suitable for outdoor riding and photo shooting. Note: The data are all measured manually, please allow 1-3mm error due to manual measurement. allow 1-3cm error due to different light and display, there may be some color differences, please refer to the actual item received.