It had both an upper and a lower light to distinguish it from the three other lighthouses in the Firth of Clyde.

The "double lights" were replaced by a powerful flashing system in 1901.

The lighthouse tower is 29 metres (95 ft) in height; there are 128 steps to the top.

Under normal conditions, its light (three white flashes every 30 seconds) is visible for 17 nautical miles (31 kilometres).

They were also filming locations for "Queen Victoria Syndrome", the first episode of season 5 of The Crown.