Imperforate sheetlet (5s) from the Isle of Stroma, issued in 1969 and depicting three orange-eyed white cats.
U/M / Unmounted Mint / MNH / Mint Never Hinged.
Stroma is a Scottish island, located in the Pentland Firth between Caithness and Orkney.
Background information on the 1960s labels that bear the island's name is reasonably hard to come by. However, the island's abandonment by its last permanent residents, in 1962, suggests that its stamps were produced for collectors rather than as part of any genuine local postal service. Either way, the stamps of Stroma count as Cinderellas by virtue of the island being part of the UK, and not an official postal administration in its own right.