I bought this as it has some good reviews for the price! It arrived fine with no problems, and was very easy to assemble - just 4 screws and you even get a rather weak mini-spanner to tighten the nuts with. However, having assembled the unit, I was horrified to find it didn't fit any of the doors in my flat :(
The long black plastic bar that "sits" on the horizontal door frame top was just too thick to sit safely on my door frame, and there's no way I could have even inserted the metal safety clip to keep it in place, as the thickness of my door frame edgeing is only about 1cm deep.
If you are going to use this then make sure the top of your door frame is I'd say an inch thick.
I think someone else has posted the dimensions elsewhere in a review on here, but save yourself a lot of trouble and make sure you have a suitably thick door frame BEFORE you order!. I have had to return mine, obviously unused - as it won't fit on any of my door frames!
Maybe "Amazon" should include minimum door frame requirements in their product description to avoid returns, or maybe it's just me who has the wrong type of door frame edgeing...