Stone Mountain Limited (SML) Phoenix Remote Speaker Microphone (RSM) was built for workers in demanding and harsh environments. It passes MIL-STD-810G for vibrations and shocks, and it meets IP-68, making it resistant to micro particles and water submergible. SML custom designed the Phoenix RSM to reliably connect to Sonim's SecureAudio Connector on the XP5s and XP8 handsets. This allows the Phoenix RSM connector to screw into the handsets and draw power. The Phoenix RSM has a large tactile PTT button and one touch high and low volume controls.