They show the partition type, either GUID_partion_scheme, APFS Container Scheme, or MBR_partition_scheme. You can see similar information from the command-line: $ diskutil listĢ: Apple_APFS Container disk1 500.0 GB disk0s2 Before that it showed 374 MB capacity, and Master Boot Record (MBR) for the partition map type. The drive displayed above is already converted. Selecting one in the upper-right pane shows the relevant information: You can now see the different USB drives attached.
and select USB from the Hardware section. Select About This Mac from the Apple menu in the top-left corner, click on System Report.
It turned out that I first had to create a GUID Partition Table (GPT) on it to use the full capacity. My new LaCie rugged USB-C drive showed only a capacity of 372 MB instead of the 4 TB that I had bought, when I formatted the disk on Mac OS X High Sierra.
