Bowflex’s adjustable dumbbells have been a huge hit with our readers, and today you can save $100 on the smartest set they sell.

The SelectTech 560s can adjust from five to 60 pounds in 2.5 pound increments, so you can add more weight as you get stronger without dedicating half of your spare bedroom to a weight rack. The main advantage of the 560s over the more popular 552s, and the reason they’re more expensive? Bluetooth.

Before you start rolling your eyes, the smart features here actually seem, well, pretty smart. The weights sync with a smartphone app that shows you how to perform over 70 different exercises, then automatically tracks your reps and weight for each one, so you can see how you’ve improved over time. Your muscles won’t know the difference, but it might give your brain the motivation it needs to keep pushing.