The voiced labiodental stop is a consonant sound produced like a [b], but with the lower lip contacting the upper teeth, as in [v]. This can be represented in the IPA as 〈b̪〉. A separate symbol that is sometimes seen, especially in Bantu linguistics but not recognized by the IPA, is the dbligature〈ȸ〉.
The voiced labiodental stop is not known to be phonemic in any language. However, it does occur allophonically:
Its phonation is voiced, which means the vocal cords vibrate during the articulation. However, in some languages (like Swiss German) it can just mean that this consonant is pronounced shorter and weaker than its voiceless counterpart, while its voicedness or lack thereof is not relevant. In such cases it's more accurate to call such sounds lenis or lax.
It is an oral consonant, which means air is allowed to escape through the mouth only.