What does attribute WCHAR Name[1] means in Windows Kernel?

I was wondering what does this structure means

typedef struct _VOLSNAP_NAME {  USHORT  NameLength;  WCHAR   Name[1];} VOLSNAP_NAME, *PVOLSNAP_NAME;

I'm not understanding why the structure has a NameLength value since the Name length seems to be always 1.
I also don't get why is the WCHAR Name[1] size present : should'nt

WCHAR Name;

be enough ?