I'd be more descriptive, but I'm not exactly sure what they are.
I have my guesses, but I just wanted to know if anyone had an actual answer.
I pulled them out of a bin at my local bicycle co-operative, and because no one there had any idea what they were, I took them. I've been using them as a dummy hood in the crook of my moustache bars, and they work great for that. Better than an actual dummy hood in fact, the dumbbell shape fits just perfectly. On a drop handlebar though, I can't imagine where these things would fit comfortably, or why they would be any improvement over a normal dummy hood.
As far as I can tell, they are really awkwardly shaped dummy brake levers (at least I've been using them as such). They are made by Dia-Compe, and they do have the right shape clamp to attach to a handlebar.