Bangle.js 2 is an open, hackable smartwatch. With a sunlight-readable always-on screen, 4-week battery life, complete flexibility, and complete control of your data, Bangle.js 2 is a refreshing break from expensive smart watches.

You can install new apps from the web or develop your own using JavaScript. All you need is a Web Browser (Chrome, Edge, or Opera) and you can upload apps or write code to run on your watch wirelessly! Bangle.js is waterproof and comes with Bluetooth Low Energy, GPS, a heart rate monitor, accelerometer, magnetometer, pressure sensor, and more. 

Bangle.js 2.0 specs:

• IP67 Waterproof (max 1 meter for 30 minutes) Please note: IP67 does not mean you can wear it while swimming.
• Nordic 64MHz nRF52840 ARM Cortex-M4 processor with Bluetooth LE
• 256kB RAM, 1MB on-chip flash, 8MB external flash
• 1.3 inch 176x176 always-on 3-bit color LCD display (LPM013M126) with backlight
• Full touchscreen (6H hardness glass)
• GPS/Glonass receiver
• Heart rate monitor
• 3 Axis Accelerometer
• 3 Axis Magnetometer
• Air Pressure/Temperature sensor
• Vibration motor
• 200mAh battery, 4 week standby time
• 36mm x 43mm x 12mm watch body, with standard 20mm watch straps
• Full SWD debug port on back of watch