Size: ball head diameter 20mm, total length 55mm. ▶Lifetime warranty: If you have any questions about product quality or use, please contact us in time, our products will provide lifetime warranty ▶Sturdy and durable: The 20mm Double ball head design adapter is made of aluminum alloy stainless steel CNC precision processing, which is sturdy and durable, and the high-quality non-slip rubber is non-slip and wear-resistant, which plays a good protective role for the double ball head adapter ▶COMPATIBILITY: Compatible with iBOLT Mount 20mm Ball Adapter: This 20mm to 20mm connector is compatible with the iBOLT Mount 20mm Ball Adapter, and can be connected to all brands of 20mm ball head mounts and phone mounts with a 20mm ball head, including standard Bulletpoint mounting arms. ▶Professional installation accessories: With the double ball bracket design, you can flexibly rotate the device 360 ​​degrees and place the device exactly where you want. If you want to fix the 20mm ball head adapter of the device more tightly, you can use the mounting arm to clamp the ball head, adjust it to the appropriate angle, and easily tighten the 20mm ball head adapter. ▶Note: This product only contains a 20mm ball head adapter.