No "extra" slot. This model comes with 12GB of RAM like this:
- 4 GB soldered on motherboard
- 1x8GB module in the one and only SODIMM slot
The processor, i7-7500U, supports 32GB of memory, but i've seen it reported, on a well-known compenents manufacturer's upgrade site, that 12GB is the max memory for this board.
It takes DDR4-2133 SODIMM modules.