The caves contain wrinkles, stalictites and stalagmites, columns and ropy lava. They are the most extensive and accessible set of lava caves in Victoria. Only one cave, Harmans 1, is open to the public. Wear appropriate footwear and clothing and take a torch.

Bentwing bats spend winter in some of the caves. To avoid winter food shortages the bats slow their body systems down in what is known as torpor where their body temperature matches that of their surroundings. Disturbance during this period can kill them. These caves are therefore closed during the torpor period.