From Phonak's literature:
Phonak Naída B, the 5th generation of the world’s most trusted power hearing aid, has been developed for the broad diversity of severe to profound hearing losses. Powered by the innovative technology of the Phonak Belong™ platform, Naída B offers a UP and a SP model in four performance levels and the most feature-rich, rechargeable hearing aid from Phonak: Naída B-R RIC.
Naída B provides fitting flexibility with Adaptive Phonak Digital Contrast, a new slow compression option which increases the envelope cues for speech. It also utilizes dedicated features such as Binaural VoiceStream Technology™ for improved speech understanding and SoundRecover2 for more audibility of high frequency sounds. With the enhanced Roger and directional, listening effort in the near field is significantly reduced.