^([0-9A-Fa-f]{2}[:-]){5}([0-9A-Fa-f]{2})$ Matches: ✓ 00:1A:2B:3C:4D:5E ✓ 00-1A-2B-3C-4D-5E
^([0-9A-Fa-f]{2}[:-]){5}([0-9A-Fa-f]{2})$
Both are valid. [:-] matches either.