Originally from advertising for Ronseal woodcare products this phrase was quickly picked up by the public and turned into a general purpose phrase meaning "the name describes exactly what it is". This must be one of the most successful advertising slogans of all time. Of course Ronseal have trademarked it!
Second class post - it does exactly what it says on the tin!
by ivan o'shun October 18, 2007
Someone with little technical knowledge who gives a review of a product or service would say this phrase.
They would feel as if they are handing out good advice to people; But in reality they dont have the experience or analytical ability to give a detailed review.
John: "How is your new camera?"
Bill: "it does exactly what it says on the tin"

John has no idea whether the camera is good or not. He just knows that it takes photos.
If Bill had more technical knowledge, he would have given more useful information.
by Jamesrice March 6, 2021
The label on the item in question is self descriptive, and leaves no doubt as to what is contained in the package.

"Tin" refers to what they call "cans" in England.
"This label says 'fireworks'. What's in the box?" "Exactly what it says on the tin.
by Dennis October 10, 2003