I third any of the logitech options. If you don't want to spend a lot and don't care about backlit keys, the K380 or K480 (which is a K380 with a slot for your phone) are under $50 and have the same functionality as the K811.
The only issue I've had is that it disconnects when the computer restarts and take a while to reconnect. That means if you need to hit the option key when you bootup to change the startup disk, it won't work fast enough.