Independent Suction Cup Are Designed to Attach Firmly to Smooth Surfaces & Provide Stable Support. Firmly Locking the Phone to Keep It Still. This Mobile Phone Holder Will Not Damage the Surface of the Phone Case & is More Convenient to Use. It has Been Optimized with a Bottom Opening That Makes It Easier to Insert Cards & Easily Push Out From the Bottom, Improving the Issue of Difficulty in Removing Cards in Other Products.