4 17mm ball head bracket adapters with 1 / 4 screws, compatible for phone holder, bracket, tablet holder The 17mm ball head bracket is compatible for sports cameras and driving recorder with 1 / 4 interfaces This 17mm ball head bracket is designed to connection any 17mm double ball head arm and bracket To ensuring compatibility, it is recommended to check if there are 1 / 4 inch screw holes at the bottom of the camera This 1 / 4 inch to 17mm ball head adapter is compatible for global positioning device stand and other brands ' 17mm double ball head arms Due to its 360 degree rotation, you can use it to build a phone camera stand or use it in conjunction with a sports camera inside the car