Polar M450
DescriptionPolar M450 GPS Bike Computer to rival the infamous Garmin Edge 25 and other pocket sized GPS cycle-computers. Optional HR strap.
Physical & performance 
Dimensions53 x 78 x 14.0 mm
Display size34.65 x 34.65 mm
Display resolution128 x 128 pixels
TouchscreenNo
Color displayNo
Weight51 grams
BatteryRechargeable via USB
Battery life16 hours
Water ratingIPX7
GPS enabledYes
GLONASSNo
Maps & memory 
Maps and routesYes
Ability to add mapsYes
Accepts data cardsNo
Sensors 
ANT+ cadence/speedNo
ANT+ heart rate strapNo
ANT+ power meterNo
ANT+ Trainer Control (FE-C)No
Bluetooth smart heart rate strapYes
Bluetooth smart cadence / speedYes
Bluetooth smart power meterYes
Features 
Power meter compatibleYes
Recording interval1 second
Virtual partnerNo
Biometric altimeterYes
CompassN/A
Electronic gear shift displayYes
Live trackingNo
Strava live segmentsNo
Temperature displayYes
Display GPS & sensor dataYes
Shock resistantYes
Wireless connectionYes
Smart notificationsNo
Automatic syncNo
Other- Instant data sync, training analysis and sharing via Flow app and web service. Plus, Polar Flow syncs with Strava.
- When you want to know the effect of a training session, Training Benefit will tell you exactly what you need to know.
- Fitness and Orthostatic Tests
- Training Load and Recovery Time
- Smart visibility front LED light for safety
Links 
View onAmazon
Amazon US rating4.4 out of 5 stars