The Yaesu FPR-1 Monitor Unit is an option exclusively for the Yaesu FTM-350R. With the FPR-1, others can hear your transmissions during emergencies, special events, etc. This unit has a built in speaker, and you can select Low or High volume. There in an LED indicator that glows green when a signal is being received, blinks slow green when a Selective Call was received, blinks green twice for data transfer, glows red during charging and blinks red when battery voltage is low.