[CentOS] which uuid to specify a raid in fstab

I'm confused about which UUID to use to identify a software RAID in fstab.

lsblk -fs shows:

md127p1   ext4    c43af789-82aa-49e9-a8ed-acd52b1cdd58 /y
--- md127   ext4  39c20575-4257-4fd7-b5c8-8a15757e9e8e
  --- sdb1  linux_r hostname:0
                  af77830e-8cfd-9012-62ce-e57105c3bf6c
      --- sdb
  --- sdc1  linux_r hostname:0
                  af77830e-8cfd-9012-62ce-e57105c3bf6c
      --- sdc linux_r hostname:0
                  af77830e-8cfd-9012-62ce-e57105c3bf6c


mdadm --detail

gives for both md127p1 and md127

UUID : af77830e:8cfd9012:62cee571:05c3bf6c


I want to add some disks to the server, not to the raid and I wanted to
avoid trouble with the names.

Any help would be appreciated.

Barry