A lens cap for the Sony RX100M2 and possibly the RX100 (not tested).
It is designed to be used with an adhesive gasket (cross section of max. 13x5 mm). Cut it into a piece with a length of approximately 212 mm.
UPDATE1: There will be a re-design for a 13x5 mm gasket
UPDATE2: Made it more simple, added an indentation to fix the gasket in place while putting it on the camera
UPDATE3: Didn't pay attention to the golden rule: "No indentations"! Pretty hard to remove the support behind it, will add a v3-1 without one. If you have a high quality gasket with good adhesive you want to use this one.