Prevents drop bars from dinging your top tube.
kashimax five gold top tube protector.
It prevents your drop bars from denting your top tube in the case you accidentally swing it your cockpit and it makes contact.
They're only useful for frames with super narrow tubing as found on NJS bikes and cost an arm and leg considering what you get.
EDIT: To clarify, I don't use this product, but rather a strip of bar tape which I imagine is equally effective at preventing top tube dings.
Oh right. I was thinking about the usefulness of protecting the top tube in general, not with that specific item..
Does seem kind of unnecessary to buy it when all it takes is the leftovers from one bar taping to protect the tube.
And here I was thinking it was a bike when all the time, you were talking about the cancerous growth on the top tube.
Sorry, it's been a bugger of a day at work
I had a good bike ... so I FIXED it