[arnold]

Looking at that spring, it is a lot more substantial than many of the cheapies. I think it looks a high quality version.

[Not a Number]

If you want to attach the adapter on a semi-permanant basis on a lens remove the small screw and spring and store them away were they won't be lost. I would not reinstall the screw as without the width of the spring the screw may go in to deeply and bind and damage the threads on the lens. Apply some thread locker to the thread. Medium (blue) strength should be sufficient or you can use high strength (red). Red will require heat to remove the adapter.

[Beepaitch]

Brilliant detailed responses fellows, thanks.