How to adjust volume on Phonak hearing aid

How can I adjust the volume on the Phonak aids in my possession?. I am in remote area and have not access to professional help. I am not sure of the model. However I am attaching ohoto of one of the Hearing Aids, hoping someone can identify them.

I don’t see any volume wheel or rocker switch so you cannot mechanically adjust the volume. But you should not want to increase the volume on hearing aids that are programmed for someone else’s hearing loss.