This is a somewhat small charging pad, which has a soft - touch finish on the top so that your smartphone doesn't slide off of it. (androidheadlines.com)
I have a number of cases for both devices, and after putting on a case, no more issues with the device sliding off of the charger. (androidheadlines.com)
With your hands on the side of the ball it is necessary to squeeze the ball to keep from sliding off. (fitnessdoctrine.com)