Disappointed. I’ve had these chairs almost 3 months and the screw require constant tightening.  It is also developing some sort of black matter.  I imagine it’s from the chair swiveling
. I have 4 total chairs and all 4 have this issue. 
I’d I could return without the hassle of disassembling, mailing back (probably at an additional cost) I would.  
The chair itself is quite nice.