Here the price and performance 1

For my Sony DSC F828 I ordered this 58mm lens cap.
It has an internal clamping with multiple threads and sits comfortably and safely on the lens.
An eyelet for a ribbon is present but selbiges not there. (Was also not part of the product description.)

Inexpensive and good to handle. Also, the material did not disappoint.
A solid idea and therefore a strong buy recommendation.