I purchased this extension Tube with the express purpose of trying to convert old slides and Negatives into a digital format using my Canon 550d (The process does produce fantastic results with no grain, unlike a scanner, but I digress). The item was received well packaged without even any damage to the box. The Tube also comes with a black carry case which would easily fit a f1.8 50mm lens. The lens fits well, making good smooth contact. The auto focus mechanism works well but is not quite as fast as a prime lens alone (though for my purposes that was unnecessary).
All in all it is a good product, at a good price and is a welcomed purchase.