The best alternatives to Strap Swap are Android Wear, ChargeKey, and AURA Band. If these 3 options don't work for you, we've listed a few more alternatives below.
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Intercom for Startups— Advanced AI-powered features at a 90% discount
Tracks your fat/muscle percentage, hydration levels, heart rate and activity. Moreover it pays for your activity. Live and fully funded on Kickstarter.