Previously used the Logitech Illuminated Keyboard K740 and the Logitech Wireless Illuminated Keyboard K800 before moving to this keyboard. Everything is in perfect shape and completely functional as intended. Continue your service with your kin. Even while it was simple to swap out the K800's batteries (two Ni-MH AA cells), those batteries were not a good fit for the gadget in question. A short lifespan for the battery. I needed to refuel rather frequently. And because they have a memory effect, we had to make a choice: either we placed it on charge for the night, but we frequently change the batteries, or we entirely discharged it, but the keyboard became wired at the most inconvenient possible moment. The Li-Polymer battery is already installed in this keyboard. There is widespread concern that it cannot be replaced, which would mean that using the keyboard would become increasingly difficult within the next two to three years. He is able to adapt quickly. There are step-by-step instructions available online. The sale of batteries has already begun. But when you open up the compartment where the batteries are stored, all you'll find is a lot of empty space. It would not be difficult to cram a battery with a capacity that is six times greater there. If it came with a battery like that, the keyboard would be ideal.