Hello, you can compare these 2 sites which in fact could give the answer to your question because AC511M is compatible with UP2516D and UP2518D is similar especially at the level of the foot, however if the system of fixing under the monitor is not present or unsuitable on UP2518D think of asking Digitec.ch if the stand adapter is supplied with AC511M.

https://store.ezytronic.com.my/products...
https://www.displayspecifications.com/en...

Also ask Digitec.ch if you have a right of return for AC511M ...

PG