3.7V/800mAH Replacement Battery for Plantronics K100， Plantronics PR-423350

however when this George ponder 4wp central.com here to bring you a video review of the Plantronics k100 bluetooth speaker phone now the speaker phones being offered over at the WP central accessory store for seventy seven ninety five it's a rather sleek low-profile speaker phone you've got an FM transmitter button a mute button a center multifunction button and then a rotary dial to control your volumes large front facing speaker to noise cancelling microphones up top microUSB to the side power it on press and hold power on takes a couple of seconds but it comes on connected and then it connects to your phone now what I feel is the weak point with the speakerphone is the ringer volume go ahead and dial my phone have it ring if it will connect it's ringing that's your ringer now I can hear my phone ring er but in the car with car noise your stereo you can't hear this chirp doesn't even