The universal adapter for custom phone cases is another option for securely attaching your smartphone to a COMPIT or +COM/UNIT holder. The adapter, which is made of sturdy plastic, and adheres to the phone's hard case using 3M self-adhesive film. The adhesive film guarantees strong adhesion. Your smartphone can then be attached to the system by simply clipping and turning it into the wide bayonet mount.The manufacturer recommends hard-backed packaging with a smooth surface for maximum adapter functionality. Dimension: 60 x 60 x 4 mm Smooth packaging surface.