In the following 1-2 disk Synology Disk Stations, we can install a 2.5" SATA hard disk (intended for laptops) or an SSD drive in the 3.5" slot with the help of this adapter.

Compatible models:
DS216j
DS215j
DS115j
DS214 se
DS213air
DS213j
DX213
DS212j
DS116
DS115
DS114
DS112+
DS112
DS112j
DS211
DS211j
DS111
DS210+
DS210j
DS110+
DS110j
DS209+II (S/N: **GCN*****)
DS209 (S/N: **G4N*****)
DS109+
DS109
DS109j

This way, on the one hand, the power consumption of the NAS can be further reduced, and on the other hand, the laptop disks operate almost silently. The smaller current consumption results in less heat production, so that with normal use, the device's internal fan usually does not start, so even its consumption can be saved, and noise production can be avoided.

We need to buy as many adapters as we plan to use 2.5" disks, and we can even mix 3.5/2.5" size disks in the NAS.