Xiaomi MI Band 2 Fitness tracker,
With Heart Rate Monitor,
OLED Display with touch button,
Activity Tracking.
Sleep Tracking, Calls,
TXT, Email Alerts,
IP67 Splash Resistant,
up to 20 days battery life
Compatibility
Devices with Android 4.4, iOS 7.0 or above with Bluetooth® 4.0 support
I'd be cautious of some of the aliexpress or ebay versions out there as a number of people are reporting/reviewing some of these as knock-offs.
This seller however looks legit. Another place to get them would be DX.com who have them for about $24USD including a second/different colour silicon band.
Gearbest has them for 22usd
I got this from gearbest 2 months back. Unfortunately it didn't pair with my phone(Samsung s2 as its Bluetooth 3 and not 4). But it works well for time, pedometer and heart rate measure.
Got one from banggood from memory when they first came out.
Was about this much a year ago?!
https://www.aliexpress.com/item/Original-Xiaomi-Miband-2-Mi-…