The Garmin Forerunner 645 Music is a smartwatch compatible with iOS and Android and includes real-time heart-rate monitor, steps, sleep, and calories. It has 240 x 240 screen resolution and an always-on display capability. It has an on-screen battery indicator, phone notifications and vibration alerts. It includes inactivity alerts that remind you to move if you are sitting for a long time. It has a find my phone and find my watch feature, can control playback of music stored on your smartphone, can control playback of music stored on your watch, and dismiss phone calls from the watch. Has WiFi, GPS and NFC. The manufacturer offers changeable straps and has weather at-wrist. It can store music on the device and stream it to headphones wirelessly. However, to get music on the watch you have to connect using the included charging cable to your computer and you can't do it through the built-in app on your phone wirelessly. A strong feature that Garmin provides is the ability to interface with optional accessories like external heart-rate sensor chest straps, speed/cadence sensors, foot sensors, VIRB cameras, and others. It also has quick pin disconnect for replaceable watch straps. It has multi-sport tracking features: running, strength training, cardio training, elliptical training, stair stepping, floor climbing, Indoor rowing, yoga, golf, skiing, snowboarding, XC Skiing, paddle boarding, rowing, cycling, indoor biking, swimming, pool swimming metrics: lengths, distance, pace, stroke count/rate, calories, swimming stroke type detection for (freestyle, backstroke, breaststroke, butterfly), and swim efficiency (SWOLF). Its dimensions are 1.7 x 1.7 x 0.5 inches (LxWxD) and it weighs 1.5 ounces.
Standalone GPSStandalone GPS means you connect to GPS from your watch without bringing your phone with you.
DiameterThe diameter of the case, measured to nearest tenth of an inch.
Display sizeSize of the active screen, to the nearest tenth of an inch.
WeightWeight of watch in ounces.
ThicknessThickness of the watch measured to the nearest tenth of an inch.
Case materialPrimary material used to manufacture the case, excluding the display.
Crystal typeThe material used to protect the display. Often it’s made of a mineral such as sapphire or quartz, or other materials such as glass or plastic.
Chemically strengthened glass
Depth and duration
Depth and durationHow resistant the watch is to submersion in water, as tested by subjecting the device to a water pressure equivalent to the depth the manufacturer claims the smartwatch can withstand.
164 feet for 10 minutes
Heart-rate monitorIndicates what type of heart-rate monitor is used, if at all. The two main types are active and stationary. Stationary heart-rate monitors measure your pulse only at intervals you choose, mostly at rest. Active heart-rate monitors measure your pulse continuously, or automatically at variable intervals.
Phone compatibilityIndicates which phones, either specific models or the operating system they use that works with the watch.
iOS and Android
Battery lifeClaimed number days, often a range, manufacturer says the watch will function on a charge.
Touch screenIndicates whether the watch can be controlled by touching its display.
Display typeTechnology used by the display, such as OLED, AMOLED, Super AMOLED, LCD, or e-paper.
NFCA short-range wireless technology that triggers a transaction between the watch and another device, usually by bumping them together. On smartwatches, it’s most often used to initiate the pairing sequence with a new phone or tablet to authorize payments at a retailer’s pay terminal.
WiFiA long-range wireless communication technology that enables a smartwatch to pair with a smartphone and with other devices within a home network or remote location via the Internet.
CellularHas the ability to connect to a cellular network without a smartphone.
Standalone musicStandalone music means you connect to your headphones from your watch without bringing your phone with you.