Features: brand new and high quality 5 types of 17mm ball adapters can be used by themselves Made of engineering rubber, good toughness, not easy to break. Double ball adapter extension joint connecting bracket for 17mm magnetic car phone holder. Round magnet for head is more stable to fix the phone, double ball for head rotation adjustment angle. Can be installed on car recorder bracket/ car phone holder, etc.mobilephone holder, tablet stand, recorder, GPS navigator-, etc Specifications: Material: Rubber+plastic Ball Head: Approx. 17mm/0.67" Name: MobilePhone Car Holder suitable for 17mm Connector Ball Diameter: 17mm Types:5 Types Optional Top Joint Specifications: Two Ball Joints of the Same Size Interface: 17mm Ball for Head Note: Please allow 0-1cm error due to manual measurement. pls make sure you do not mind before you order. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you Package includes: 1x Ballhead Extensiont Joint