Amplicom PowerTel 601 Wrist Shaker Landline Telephone Accessory Visual LED call signaling Up to 50 hours charge in standby mode Serves as additional emergency transmitter for the PowerTel 680 or PowerTel 7 Series telephones with a corded base Works with PowerTel 500, 580, 580 Combo & 680 and the PowerTel 7 Series