No, this is useless. A heart rate/blood oxygen level sensor should attach to your finger or wrist so you can keep it on while you're doing things. Most sensors

No, this is useless. A heart rate/blood oxygen level sensor should attach to your finger or wrist so you can keep it on while you're doing things. Most sensors do that, but this one doesn't, and the form factor means it can't. Making it plug into an iPhone docking port adds some novelty features, but they compromised core functionality to enable it.