See clamp Picture 1, 2, 3, 4. Edit: the pictures shown in the wrong order even though they are posted correctly ?Picture 1 shows how wide it can go. Picture 2 shows how tight it would go when I first got it. There was something catching the screw mechanism which caused too much friction. Picture 3 is after I applied WD40, a lubricant.I tried using other tools and nothing helped except WD40. Without that, if I kept trying to close it, eventually it would be so tight that it couldn’t move it at all.I like the concept and the sturdiness. If feels larger than the pictures, but it seems like a great size. I was pretty frustrated that it didn’t work out of the box and I was lucky I had some WD40. I took off one star of my review for the difficulty and because the knob had scratches when I received it. It’s possible that someone else had the same issue with this product and sent it back after not being able to work with it.I'm one of those ppl that can't handle even a pen on the desk without purpose; this is perfect because of the rotation feature - out of sight, out of mind, well, that is until you need it, and its easier than adding a drawer; A+I installed this on my standing desk which has no compartments for storage and am loving it so far. The installation was very easy and the swivel is smooth. It holds all of my pens, sticky notes, and flash drives. It's a bit pricey but it's exactly what I needed. I didn't want to screw holes in my desk like some of the alternatives.Poor quality. The one I received would not accept the top screw at all. I ended up finally just putting a twist tie through the hole to make it usable.Edit: I had this review at 3 stars, but I'm knocking it down to one as they keep hounding me to delete my three star review in exchange for Amazon gift card of $30. I've gotten 7 separate emails from them. I can't recommend buying from them, nor trusting the high reviews.Didn’t work with my desk.You can clap it at the edge of your desk and tuck it way. Very practical and convenient!