Polar H10 Heart Rate Monitor – ANT+ , Bluetooth – HR Sensor for Men and Women – Built-in Memory

While many gyms are finally modernizing to BLE, not all have. This heart rate monitor is the only one I know that should work with the vast majority of gym equipment whether the 5 kHz, ANT , or BLE. This strap also can broadcast to two devices at the same time so you can log your workout to your phone while also seeing it on the equipment. I actually bought this after misplacing my previous one. If you use the app you can unlock some interesting features like a 5 minute health test where you only have to lie down (I think this estimates VO2 but I have not looked into how other apps have imported it) and a few other tools to help you achieve specific goals. As an electrode this is considered the gold standard in heart rate monitors.

I've been with the products for a few days, but I really like it. Makes it easy and natural to track your calories burned, I also makes it for a fun game so always try to keep harder.