I'm using the Monoprice ones that are identical to the Fully Jarvis.

This version supports upto 27 inch monitors: https://www.amazon.com/Smooth-Motion-Monitor-Adjustable-Spring/dp/B074QZFTLG/

And this one supports upto 34 inch monitors https://www.amazon.com/Monoprice-Smooth-Motion-Monitor-Adjustable/dp/B01J6KMNOK/