The Selfloops Spark app is available for Android, iPhone and Apple Watch and support a large variety of Bluetooth sensors.
The app supports the Bluetooth FTMS standard, this means it supports indoor bikes and indoor bike trainers, treadmills, rowers.
It supports the Cycling Power Bluetooth standard, so bike power meters that use this standard are supports (the vast majority).
It supports the Cycling Speed and Cadence Bluetooth standard.
It supports Concept2 machines, including the rowers, bikeErgs, skiErgs that use the PM5 monitor.
It supports heart rate monitors that use the Bluetooth standard.
The Selfloops Spark app does not support ANT+ sensors.
If you have ANT+ sensors, you need to use a bridge device that will allow you to connect the ANT+ sensors to the Selfloops Spark app.
These are the two most popular ANT+ bridges: