Bluetooth Headset for HX891BTThe SSM-BT20 is a wireless Bluetooth 5.0 headset designed for all Standard Horizon Bluetooth-compatible transceivers.Great for Boaters needing handsfree VHF operation. The SSM-BT-20 has been updated for better audio quality and improved performance of the PTT multi-function button.The Standard Horizon SSM-BT20 Bluetooth Headset is compatible with Standard Horizon’s Bluetooth VHF Radio (Sold Separately). Specifications:Type: MicrophonesBox Dimensions: 2″H x 4″W x 4″L WT: 0.15 lbsUPC: 788026181261