What happens when you pair a speed sensor With the #1 selling bike trainer in the USA? You get a combo thats ready for any virtual or non-virtual training ride. Its the ideal setup for budget-conscious athletes looking to join fun, virtual communities, like ROUVY and Swift, without a traditional smart trainer. Simply install the magnet less speed sensor on the rear wheel of your bike, mount your bike to the solid fluid2 trainer with our innovative Clutch knob, connect to your virtual training app of choice via Bluetooth or ant+ and voilà! - youre ready to sweat.