The SPM-3100A and E by PRYME is a heavy duty speaker microphone with an antenna jack. The unit features both a conventional side-mounted and front-mounted Tactical Touch Push-to-Talk button for ease of operation. Both have a loud front-firing speaker and an earphone jack for additional privacy. (Earphone sold separately.) SPM-3100AP versions contain a Panic Button which can be used to trigger panic (or other functions) if the feature is supported by the two-way radio the microphone is being used with. The SPM-3100A Series is for radios with an RF connector built in to the radio's audio accessory jack. The E series is for radios that do not have a built-in RF jack and attaches instead to the antenna connector.