In Italy, a membership card is required for all gay cruise bars and clubs.
Often that is the ARCO (Anddos) card.
If you don't have an ARCO card yet, you can usually acquire it
at the entrance of the venues that require the card.
(5 € for three months, 17 € for one year.)
When you acquire the card you need to show your photo ID,
after that you only need the membership card.