Best Buy: Logitech mm50 Portable Speakers for Apple® iPod™ and Most MP3 Players Black 970173-240
TTVXO Battery for Logitech MM50 Speaker of Battery NTA2335|Smart Accessories| - AliExpress
Logitech MM50 speaker system: removing IR sensor. This sensor is always "on", draining the battery in less than a week. I lost the remote, so I have no need for the sensor.