Instruction: Answer the given question by extracting information from the supporting document.

Input:
Question: What is the length, width, and height of the base? The small square black part where the clamps are.
Document: Very no frills, but very effective. Strong, clamps on my desk (surface is 2x4's) and is very sturdy. Its not 5 stars, because I don't think the arms are quite long enough to effectively use 3 monitors. You'd be using somewhat small monitors.
so far its holding up 2 20inch asus monitors and a 27inch asus monitor with no problem. it seems to be staying attached very well/ its held in on the bottom with 2 flat screw down clamps and the base of the clamp is adjustable to almost any size desk. i personally had to add a piece of wood, cause mine is on the endge of a glass table and if i didnt add it i woulda cracked my glass.
The main thing of course is that the monitors are not taking up a bunch of desk space. The part that I do not like is the arms do not adjust up and down independently, you must move both up or leave both were there they are. They do articulate and tilt though, and very smoothly too.
I have a 25, 20, and 19 mounted to this stand it it's perfect for what I need. The only thing to note when getting this is that of the 2 monitors that are side by side, they will tilt and rotate but not change height independently from one another.
Unfortunately the only issue that prevents a higher rating is the inability to obtain a secure tightening of the monitor arms without using your own tools. I do not recommend relying on the included allen wrench but rather get a higher torque wrench or drive to get some muscle on the ring clamps.
Okay, it does hold up monitors. Fine.But what I was trying to do was create a set up where I could mount my monitors at standing height, then easily switch to sitting when I got tired of standing. You could do that with this set up but you'd have to get out our allen wench and loosen a few bolts while supporting the weight of the monitors, then wiggle the whole thing up or down.
Recommend this particular stand as it gives huge flexibility for CAD users and very adjustable (VIVO should maybe make the arms &#34;all equal length&#34;- use the longest from the column-keeps there inventory down and mass produced). Like the third screen mount- use for a 20&#34; TV screen, so can work and watch at same time if I want.
If it hadn't been for the difficulty adjusting this unit I would likely have kept it although not entirely happy with the setup. My wife however wants one that is easier to adjust. The breaking point for me in addition to that was really that one bolt that was so tight it would not adjust probably just a fluke on my unit though.The bar and mount was very solid once installed. Good quality product for the most part.
Once you figure out how to get the caps off to adjust the tension on the joints, this thing is solid. Clamps like a beast to the desk if you use a screw driver to torque the clamp screws down good. Getting the monitors onto the lower (assuming you do a standard pyramid setup) arms is a bit tricky. You basically need to hold the monitor in one hand and screw it to the VESA mount with the other.
Picked one of these up because I wanted to set up 3 monitors but didn't have the length on my desk to do it.Took awhile to set up, but after I got everything together and tightened down all the (very loose) bolts on the arms, I couldn't be happier.Easy to adjust a monitor's position, and holds solid once you tighten everything down. Freed up so much desk space without having to worry about the stands on my monitors.Unfortunate to see they're out of stock right now.
Answer: I will try to upload an image, but the dimensions on the top plate is like a 4" x 4", but it is not square for the top part, has rounded edges. The depth down is 4.5".