This tower was very easy to assemble ( I’m an old lady and was able to build it by myself.) and the screws matched the holes - a good thing!  My cat loves it and started using it at once.  It is balanced and only wobbles a little when my cat pounces on it.  If I have one complaint- it would be “I wish it was heavier so it didn’t wobble”.  Then again, I do have a busy, wild, year old male cat who loves to run and pounce!