The asus laptop k550jk (
https://www.asus.com/Notebooks...) uses following RAM Modules
"DDR3 MHz SDRAM, OnBoard Memory 4 GB / GB, 1x DIMM", where the DIMM socket, which is completely different from an SODIMM. I suggest to verify with Asus which memory module you can be used to ensure that it works properly before purchase.
Cheers, Alex
https://en.wikipedia.org/wiki...
