A bilabial is one with two lips spoken sound.
Bilabial sounds are as follows:
1 The IPA does not have its own characters for this volume, therefore, is - by whom? - The [ u] used in conjunction with the Unsilbigkeitszeichen [ ̯ ] or, depending on the language that describes also the sign for the voiced bilabial fricative [ β ], to be exact with the Approximationszeichen [ ˕ ]
See also: Labial