rsync permissioning?

I have run the command

sudo rsync --chmod=a+rwx testfile testfile2

This creates a file testfile2 but the permissions on it are 755 (-rwxr-xr-x)

Can someone explain how to make it so the permissions are 777 (-rwxrwxrwx)?

Use

sudo rsync --perms --chmod=777 testfile testfile2

or

sudo rsync --perms --chmod=a+rwx testfile testfile2

Using --chmod=777 with rsync may fail:

sudo rsync --perms --chmod=777 ./testfile ./testfile2
rsync: Invalid argument passed to --chmod (777) 
rsync error: syntax or usage error (code 1) at main.c(1453) [client=3.0.9]

However, these are successful:

sudo rsync --perms --chmod=u+rwx ./testfile ./testfile2
sudo rsync --perms --chmod=g+rwx ./testfile ./testfile2
sudo rsync --perms --chmod=o+rwx ./testfile ./testfile2

i.e. add (+) permissions for user (u), group (g) or other (o) respectively.

Also (a)=all is successful:

sudo rsync --perms --chmod=a+rwx ./testfile ./testfile2

or alternatively:

sudo rsync --perms --chmod=ugo+rwx ./testfile ./testfile2

That --perms can replaced by -p with same results.

Revoking (-) permissions works the same way and even comma separated combinations of adding and revoking:

sudo rsync --perms --chmod=u-rwx,o+rwx ./testfile ./testfile2