The additional silicon padding near where your thumb goes is a nice touch and the grip itself fits my x100s very snuggly and securely without the need for a screw etc

I had tried another product for this purpose the fotodiox pro thumb grip for mirrorless digital cameras and while it worked out i was bothered by the fact that it requires a small screw applying pressure to the hot shoe to stay in place

This product which is less expensive than fujis accessory thumb grip makes holing the camera easier and in many ways safer

As is typical for lensmate thumb grips this one fits perfectly and provides a comfortable and secure grip for holding the x100s