Bower 77mm Plastic Lens Cap

I bought this Bower 77mm cap for a 300mm Takumar lens that I got recently. I did think about getting one of the more expensive center pinch type caps but I have them on a couple of other lenses I own and, while they are heavier duty than this Bower...

It might be just my situation, but also a design flaw. I managed to lose the cap that came with my lens the week I got the lens and decided to get this as price seemed good. Unfortunately, handles on the side protrude in a way that does not allow using...

this is a cheap but, functional cap. What do you expect for a few bucks?