Suptek Single Monitor Arm Gas Spring, Monitor Arm Desk Mount for 17-27 inch Monitors up to 6kg (Prime Deal), zeyi FBA

I have an old Ergotron articulated monitor are but the damn thing won't stay up unless i shove a screwdriver into it.

According to one reviewer; He bought this to replace others he bought that 'sag' and as another reviewer said it held his 28" it sounds good enough for me.

Oh and it has tension support that uses an Allen key but take note of what this reviewer said:

I would have made the same mistake too of tightening the gas strut, but that actually decreases the tension, so make sure you LOOSEN the screw to increase the tension and it holds well.