saves annoying fumbling

This part fits very well to the camera and saves the hassle of fumbling with the standard lens cap.
For installation you have to know that only a ring on the lens must be removed carefully at the camera.

The ring has no screw thread but a bayonet.
Also, the lens cap.

After that it will save you the fumbling, each time removing the cap before capturing an image and (where to put it?) And after taking a picture must back on.
What justifies a deduction of points is the fact that after installation of the cover with the lid screwed on Filter Adapter FA1 no longer closes completely.