With the RS195 it is possible to couple 2 headsets simultaneously from the following range: RS 165, RS 175, RS 185. However, the specificities of the RS195 transmitter (e.g. frequency correction) will not necessarily be applicable to a helmet of the RS 165 -175 or 185 range.
You will find the list of helmets compatible with the RS 195 on the following link of the manufacturer:
https://hf-files.s3.amazonaws.com/hdpsennhei...