Dovetail Phone ClampThe ProMaster Phone Clamp is a great way to mount your smartphone to a tripod, flex arm, studio clamp, and more, using one of its two 20 threaded ports. Or, connect it to a tripod using the integrated dovetail (arca type) foot. Its constructed of high quality aluminum and is compact and lightweight. The jaws open to a maximum size of 3 1 2" to accommodate the largest smartphones; even when a protective case is installed.