Standard Horizon SSM-21A Speaker Mic f/HX890, HX400, HX400IS, HX380, HX40 HX210 [SSM-21A] Cartography | Garmin Navionics+ This heavy-duty isolator allows multiple

This heavy-duty isolator allows multiple batteries to charge automatically from one or two alternators and prevents the discharge or ‘dumping” of one battery into another

Rating: 105 db@ 1 Meter

With its built-in GPS receiver

using this product

Standard Horizon SSM-21A Speaker Mic f/HX890, HX400, HX400IS, HX380, HX40 HX210 [SSM-21A] Cartography | Garmin Navionics+ This heavy-duty isolator allows multipleSSM 21A Speaker Mic for HX890, HX400, HX400IS, HX380, HX40 & HX210 Standard Horizon SSM 21A submersible speaker microphone with heavy duty belt clip. Compatible with Standard Horizon HX890, HX400, HX400IS, HX380, HX40, and HX210. Specifications: Type: Microphones Box Dimensions: 3"H x 5"W x 7"L WT: 0. 45 lbs UPC: 788026174768