Bought this cover for my 1Phone 4s and it fits perfectly. Looks rather nice as well and not too bulky. Also get a screen protector with it which was easy to apply, not too sure about the screen protector but it is an added extra so can not complain. I saw a few previous reviews complaining about the lock button but I have had no problem with it at all. Glad I took the risk and bought the cover.
If you're looking for a cover for your iPhone 4s, then I would highly recommend this product, at £1.45 you can not go wrong :)