Currently there is no silicone or rubber material around the sides of the case, BUT there's no need for it!
That's the great thing about Kloqe's design! The sides of your phone never come in contact with the case itself. The reason is, the case is designed with a .04 mm air gap between the side of the phone and the case, eliminating any metal on metal scratching.
So how does the case hold on? Well, if you look closely to your phone, you will see a tiny top edge adjacent to your screen. Kloqe is design to grab on to this tiny edge all the way around the top, leaving you with a perfect fit and no scratching!