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Garmin Forerunner 305 vs Garmin Forerunner 405CX

Every spec side by side, from each maker's published figures.

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GarminForerunner 305GarminForerunner 405CX
Overview
Released20062009
Display
Case sizes53.3 mm47.75 mm
Always-on displayYesYes
Display detailBacklit 33 × 20.3 mm monochrome display, 160 × 100 pixels; configurable training screens and physical buttons. Panel technology is not specified by Garmin.Backlit monochrome screen, 27 mm diagonal and 124 × 95 pixels; touch-sensitive bezel and two buttons. Panel technology is unpublished in the maker's specification.
Health and fitness
ECGNoNo
Blood oxygenNoNo
Skin temperatureNoNo
Sleep apnoea alertsNoNo
High blood pressure alertsNoNo
Body compositionNoNo
Fall detectionNoNo
Crash detectionNoNo
GPSSingle-bandSingle-band
SensorsHigh-sensitivity SiRFstarIII GPS receiver, included wireless heart-rate chest strap and optional GSC 10 cycling speed/cadence sensor; no optical wrist sensor.High-sensitivity GPS receiver with HotFix; ANT+ heart-rate chest strap, optional foot pod and cycling speed/cadence sensor. No optical wrist sensor.
Fitness featuresRunning, cycling and other-sport profiles; quick, interval and advanced workouts, course racing, Virtual Partner, Auto Pause, Auto Lap and heart-rate, pace, time and distance alerts.Heart-rate-based calorie calculation developed with Firstbeat; custom and interval workouts, courses, Virtual Partner, Auto Lap, Auto Pause, Auto Scroll and configurable training screens.
Safety featuresStores 100 locations and 50 routes; basic route display, direction to a stored location and navigation back to the start. No base maps.Up to 100 stored locations and navigation to a saved location; no base maps.
Battery and connections
Battery life (maker's claim)Up to 10 hoursUp to 8 hours
In low-power mode–Up to 14 days
Mobile data optionNoNo
Works withNo phone pairingNo phone pairing
Battery life detailInternal rechargeable lithium-ion battery; ten hours of typical use.Rechargeable 300 mAh lithium-ion battery; up to eight hours with GPS or two weeks in power-save mode, according to the English owner's manual. Garmin Slovakia instead quotes nine GPS hours.
ChargingDocking cradle with AC charger and USB cable.USB contact charging clip and AC adapter.
ConnectivityUSB computer transfer through the cradle; Garmin Training Center software and MotionBased analysis were supplied at launch. Wireless heart-rate and cycling sensor connections; no direct phone pairing.ANT+ computer transfers through a USB ANT stick; Garmin Connect and Garmin Training Center. No direct phone pairing.
StorageUp to 1,000 laps; smart recording or one-second recording.Up to 1,000 laps, 100 locations and approximately twenty hours of track points at one point every four seconds.
Design
Weight (lightest version)77 g60 g
SoftwareGarminGarmin
Case materialsIPX7 immersion protection, one metre for thirty minutes; the owner's manual says it is not intended for swimming.IPX7 immersion protection, one metre for thirty minutes; the manual says the watch is not intended for swimming.
Size53.3 × 68.6 × 17.8 mm and 77 g. Width is used as the case size.47.75 × 70.5 × 16.4 mm and 60 g, according to the English manual; Garmin Slovakia rounds this to 48 × 71 × 16 mm. Width is used as the case size.
BandsVinyl wrist strap with an expander strap; fabric strap available separately.Standard wrist strap and two additional form-fitting fabric straps for smaller or larger wrists.
Colours–Deep blue.
In the boxWatch, heart-rate chest strap, wrist and expander straps, docking cradle, AC charger, USB cable, Garmin Training Center software and documentation.Watch, heart-rate chest strap, USB ANT stick, AC adapter, USB charging clip, additional wrist straps and documentation.

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