The bigger, the better.
"[It] is thought to be used to attract females and is a characteristic of the males, reaching up to 7 inches in length."
We're talking about the nose (proboscis).
"Proboscis Monkey belong to the order of Primates, from the family Cercopithecidae and subfamily Colobinae (Bennett & Gomber, 1993). According to Bennett & Gomber (1993), in the Old World, these monkeys are divided into two groups known as cercopithecines and colobines. Proboscis Monkey are colobines. Males are much larger than females, weighing up to 24 kg (53 pounds) and reaching 72 cm (28 inches) in length, with a tail of up to 75 cm in length. Females are up to 60 cm long, weighing up to 12 kg (26 lb). This large sexual dimorphic difference is greater than in any other primate.[5]"
"Brunei (pronounced /bruːˈnaɪ/ in English), officially the State of Brunei Darussalam or the Nation of Brunei, the Abode of Peace[5] (Malay: Negara Brunei Darussalam, Jawi: بروني دارالسلام), is a sovereign state located on the north coast of the island of Borneo, in Southeast Asia. Apart from its coastline with the South China Sea, it is completely surrounded by thestate of Sarawak, Malaysia, and in fact it is separated into two parts by Limbang, which is part of Sarawak. It is the only sovereign state completely on the island of Borneo, with the remainder of the island belonging to Malaysia and Indonesia."
