Comment 5 for bug 887082

The property id can change. However, you can use a few commands to detect which property you need to change. Here's how I did it on my desktop:

Computer@User:~$ xinput list | grep G300
    ↳ Logitech Gaming Mouse G300 id=8 [slave pointer (2)]
    ↳ Logitech Gaming Mouse G300 id=9 [slave keyboard (3)]

Notice the device ID for a keyboard is included. You'll want to use that ID in the next command.

edward@Odin:~$ xinput list-props 9
Device 'Logitech Gaming Mouse G300':
 Device Enabled (142): 1

Other Stuff that isn't important to us right now will also be printed. Let's focus on the Device Enabled (142) line. It's set to 1, but we want it set to 0. To do that, we issue the following command using the two numbers (9 & 142) that we gathered from the previous commands:

xinput set-prop 9 142 0

This sets the value of 142 within device 9 to 0. Your first two numbers might be different, but you need the 0 to make sure to turn the keyboard functionality of the device off so it functions purely as a mouse.