The Sony RX100 M3 is a small, but perfect camera to have. The only downside of this camera is it's small size, so you can't handle it that easy.
I have created this perfect fit grip, so that you can comfortably hold the camera in your hand, no matter if you are using it in landscape or portrait position.
The model fits perfectly around your RX100 M3 camera, with it's strange shape. I am shure you will like this grip.