This high-strength composite double base arm with a total length of 3.54 inches is compatible with RAM & BRCOVAN all size B size 1 inch ball components, including mounting base and device holder. The main body is made of PA66+GF30% material for durability and reliability in the most demanding environments. The high-strength knob with brass thread holds your bracket firmly in the long term. Uses high quality stainless steel center screw and industrial spring.