Moved to this keyboard from the Wireless Illuminated Keyboard K800, and before it was the Logitech Illuminated Keyboard K740. Everything is in full working order and excellent condition. Continue serving with relatives. Although it was easy to change batteries in the K800 (two Ni-MH AA cells), they were ill-suited for such a device. Short battery life. I often had to recharge. And since they have a memory effect, we had to choose: either we put it on charge for the night, but we often change the batteries, or we completely discharge it, but at the most unfortunate moment the keyboard becomes wired. This keyboard already has a Li-Polymer battery. Many are worried that it cannot be replaced, and therefore there will be problems using the keyboard in 2-3 years. He changes easily. There are instructions on the internet. Batteries are already on sale. But, when you open the battery compartment, you will find just a lot of free space. There it would be easy to shove a battery 6 times larger in capacity. With such a battery, the keyboard would be perfect.