If anybody wants to replace the battery in the Microsoft Universal Keyboard, here are the details.
Rechargeable Lithium-Polymer Battery
Model Name: CA213060 PACK
1ICP3/30/60
Manufacturer: ZhuHai Coslight Battery Co., Ltd
Rating: 3.7VDC 300mAh 1.11Wh (three wire type w/thermistor)
Maximum Charging Voltage: 4.2VDC
Website: http://www.cncoslight.com/english/zhdc/polymer1.asp
Battery photo: https://www.sendspace.com/file/45ft7d
Rechargeable Lithium-Polymer Battery
Model Name: CA213060 PACK
1ICP3/30/60
Manufacturer: ZhuHai Coslight Battery Co., Ltd
Rating: 3.7VDC 300mAh 1.11Wh (three wire type w/thermistor)
Maximum Charging Voltage: 4.2VDC
Website: http://www.cncoslight.com/english/zhdc/polymer1.asp
Battery photo: https://www.sendspace.com/file/45ft7d