The "gas spring" is adjustable for the weight of the monitor so once you find a good tension point then the monitor just kinda floats there and you can push it up or down without tightening or loosening anything, it's pretty cool. I adjusted the tension once or twice in the first week or so and haven't touched them since then. The monitors tilt setting came a little loose on one monitor once but took a few seconds to tighten and has been good ever since then. The asus has been fine, I don't even think that one has the adjustment turned all the way up or anything so there should be some wiggle room.
I tried a different but similar one before those and it was pretty much garbage. everything was shaky and bouncy
https://www.newegg.com/Product/Product.aspx?Item=9SIA98C48J5088