FURUNO HS-2721 RB-2721 Handset f/FM-2721 Marine VHF Radiotelephone – PERFECT!FURUNO HS 2721 RB 2721 Handset f FM 2721 Marine VHF Radiotelephone PERFECT! Works perfectly, fully tested with guarantee. All cables are in perfect condition! Handset HS 2721 Transceiver for Unit FM 2721 including Bracket RB 2721A ***** Control, LED description POWER switch (in hanger): Turns the system on off. DISTRESS button (in hanger): Sends the distress alert when pressed more than three seconds. Alarm LED: Lights when a DSC call is received.