The whole product is made of aluminum alloy, which is more durable and strong than plastic or rubber The ball size is 25mm/1" of diameter compatible with RAM Mounts B Size Double Socket Arm and other brackets that fit this size ball Bracket is a 3-in-1 functional design, it can work for most of walkie-talkie, speaker microphone with back clip, and for all CB/mobile microphone with round knob Package Includes: 1*3-in-1 Bracket with 25mm ball, 1*hex wrench Universal Radio/CB Microphone Bracket