Here is another smartphone and GoPro mount that you can use to capture softball, baseball, and tennis matches and practice sessions. The FenceGripz Chain Link Fence iPhone Mount has bendable rubber arms. It is made of 3D printed thermoplastics. You can adjust it in 3 ways.
The FenceGripz has a foldable design. You can not only use it to mount your iPhone to fences and cross poles but also above them. It is compatible with various action cams and Android phones too. You can find this mount on Etsy.[where to get it]