Piping foreach powershell exchange permissions

I am trying to list all my exchange users default calendar permissions. I have build my command like this:

 Get-EXOMailbox -RecipientTypeDetails userMailbox -ResultSize Unlimited | foreach {Get-EXOMailboxFolderPermission -identity $_.UserPrincipalName -user Default} 

It Works just fine but what I need is calendar permissions and when I try to add ':\calendar' to my code it throws an error:

Get-EXOMailboxFolderPermission : A positional parameter cannot be found that accepts argument ':\calendar'.

Get-exoMailbox -RecipientTypeDetails userMailbox -ResultSize Unlimited | foreach {Get-exoMailboxFolderPermission -identity $_.UserPrincipalName:\calendar -user Default}

I have tried putting:\calendar and $_.UserPrincipalName in to '' or "" but no luck.