I've tested USB-C ThinkPad.
High quality product.
So far I've tested USB-C ThinkPads and MacBook Air and it works for both.
I'm using a 20v powerbank with ThinkPad slim tip out, and this adapter allows me to charge my USB-C laptops from it.
Exactly the gizmo I needed to extend usage of my old Lenovo charger after my laptop was upgraded.
I was skeptical but this actually works. Shipment was also very fast and the product arrived as advertised. Saved me from replacing all my innergie travel adapter.
Perfect size. Never overheat. Love it! Carrying it and using it everyday for my X1 Carbon.