I used MI band 2 for My fitness tracking this band is very cool and easily fit this band has too much features with Bluetooth and easily connect with your smart phone this band has oled display and 20 days battery backup this band easily track your heart rate sleeping time distance to walking calculate your steps and monitoring your calories to inform you this is very reliable to use and easy to operate battery life is very great and style and design also very attractive look like awesome and it is also available many top shopping sites like Amazon and others with best deal so I recommend you guys please buy it and use this band your life better.