The Mio FUSE has all the features you want in a fitness tracker paired with the engineered precision of Mio Heart Rate Technology. Mio FUSE takes your performance and training to a whole new level. Not only can it monitor your heart rate with peak accuracy during workouts, but it also tracks your steps, calories, distance, pace, and goal progress throughout the day. Mio FUSE FREQUENTLY ASKED QUESTIONS How do I choose the right size? Mio FUSE is available in two sizes. Size Small/Medium fits wrists 5.8" - 7", Size Large fits wrists 6.1" - 8.2". Question not answered here? The Mio Support Team is happy to help you out; send us an email us any time at support@mioglobal.com, or call us at 1-877-770-1116 (Mon-Fri: 9am to 5pm PST). Do I need a smartphone to use FUSE? To configure and sync FUSE you"ll need the Mio GO app, which is available for iOS and Android smartphones. FUSE is compatible with the following devices: IOS: iPhone 4S and higher, iPod Touch 5th gen. Android Devices: HTC One (OS v4.3+) & M8, LG G2 & G Pro2, Motorola Moto G, Moto X, Droid RAZR M, RAZR Maxx HD, Droid Ultra, Maxx, Mini (OS v4.4+), LG Nexus 4, 5, 7, Samsung Galaxy S3, S5, S5 Mini, S4, S4 Mini, Note 2, Note 3, Note 10.1, Sony Xperia Z, Z1, Z1 Compact, Ultra, ZR, ZL, Sony Xperia SP, V. FUSE cannot be synced to or be configured with a Windows phone, Blackberry device, desktop computer, or laptop. What should I do if I"m getting inaccurate heart rate readings? Inaccurate readings are usually caused by poor contact between the heart rate sensor and your skin. Make sure that FUSE has a snug fit on your forearm, about 2 finger widths above your wrist bone. If you have a very small wrist, wear FUSE higher on your forearm. You can also try wearing FUSE on the inside of your arm. What apps can I use with FUSE? You can only configure and sync data from FUSE with the Mio GO app, but you can transmit heart rate directly to any app that syncs with Bluetooth Smart (4.0) heart rate sensors. Some popular apps include: Strava, MapMyRun, RunKeeper, Endomondo, Wahoo Fitness, Pear Sports, and DigiFit. Connect FUSE as a heart rate sensor through the settings of the app you"d like to use. Can I transmit heart rate from FUSE to exercise equipment? FUSE transmits heart rate using Bluetooth Smart (4.0) and ANT+ heart rate profiles to equipment such as bike computers, GPS watches, treadmills, rowing machines, and more. To see if your device/equipment is compatible, look for a Bluetooth 4.0 or ANT+ logo, or view your product"s Specifications section on the Mio Global website for a full list of brands and models.