WMI Logical FreeSpace and Size

I trying to run this command but free and size property is not showing anything.

Get-WmiObject -Class Win32_logicaldisk -Filter 'drivetype = 3' | Select @{N='Free';Ex={'{0:N1}' -f  $_.freespace /1gb }},@{N='Size';Ex={'{0:N1}' -f  $_.Size /1gb }}