Here is a pair of adjustable dumbbells that you can control with Alexa voice commands. The NordicTrack iSelect Adjustable Dumbbells has adjustable weight from 5 to 50lbs. It comes with an adjustment knob but you can also ask Alexa to set weight to a specific amount, increase/decrease weight, and set weight presets for specific exercises.
The NordicTrack iSelect Dumbbells combine with iFIT to keep you motivated. They come with a storage tray that has an integrated tablet holder and a convenient LED display to show the current weight.