VIVO Dual Vertically Stacked Monitor Desk Mount, Extra Tall Adjustable Stand for 2 Ultrawides up to 34 inches, 22 lbs Capacity, Black, STAND-V002T

I'm running a VIVO double mount. Assuming you're probably looking at a single arm, but if you want to go the route of dual stacked monitors if you want a second one here's the one I've been using a long while now. https://www.amazon.com/dp/B00DGTP57A?th=1 I added their steel reinforcement plate too for some peace of mind, since I am also running also a VIVO sit/stand desks and wasn't sure on the build quality of the table top. https://www.amazon.com/dp/B07NNVJHRY?th=1 I've had my 34" UW on this for over 3 years now and recently swapped a 27" 1440p to a 32" 4K on top. Still holding strong.

Nice, you'll love it. The mount that holds the 2 ultrawides is THIS one from Amazon. Holds the 39" with no issues.