The first reviewer, explaining the "odd" design, almost put me off, but I took a chance and bought this hood. It's better than OK, and if I lost it, I would certainly buy a replacement. I do agree with the first reviewer - if I were designing a hood, it would not be like this, BUT IT DOES WORK and it also looks quite normal. I leave the metal adaptor ring permantly screwed into the lens. The original lens cap just clips into the adaptor as it has the same internal diameter as the lens itself. When stored in my camera bag, the plastic hood can clipped in back to front so that the whole unit is compact. When removing the hood and then clipping it in the right way round, it probably takes just half a second longer than the more conventional bayonet fitting.
I was going to award this 4 stars because of the unusual design, but as there is no competition and it does the job, I decided to up this to 5 stars.