Yes, it is awkward, but if that is the name of the thing, then that is the name of it. That being said, just because something is not incorrect doesn't necessarily mean you should do it.

I do think that adding "opening" is a good idea. It removes the awkwardness and gives clarity to the sentence by fixing the context. One of the problems with awkward sentences is that even if they are correct, and even if they say what you mean, they cause readers to wonder if you didn't in fact make a mistake somewhere. Awkwardness slows down reading and causes the reader to do extra work.

I think the last option is probably the best form, although there is nothing wrong with the option that precedes it either.