Directory and Create Mask Values

Hi there,

when issuing the sharing -l command, I will get the following output:

List of Share Points
name: apollo13
path: /Shared Items/apollo13
afp: {
name: apollo13
shared: 1
guest access: 0
inherit perms: 0
}
ftp: {
name: apollo13
shared: 0
guest access: 0
}
smb: {
name: apollo13
shared: 1
guest access: 0
inherit perms: 0
oplocks: 0
strict locking: 1
directory mask: 493
create mask: 420
}

can anyone please explain me, what kind of values are those at directory mask and create mask?

Thanks in advance!