I've been using this for a while, but I no longer need it because I replaced my projector. It securely holds projectors that are fixed in four places, and I had no problems with it. When it's shortest, it's about 40 centimeters, and it extends to about 60 centimeters when fully extended (these are approximate measurements). I'll include the screws, so you can use it right away. Please connect it in one place with a hex wrench.