Location: Trong Mai is situated in the southwest of Ha Long Bay, in Ha Long City, Quang Ninh Province, about 5km of Tuan Chau International Port.

Characteristics: The islet looks like a pair of Cock & Hen in the sea.

In a somewhat large expanse of open sea, the islet seems to grow up from the bottom of the deep emerald waters. At sunset, the islet with a height of about 12m is bright red and in a somewhat tottery position.