Colour-changing Disc-O Select technology - keep colour alternatingLED Glowstick for visibility & safetySimply push to turn the light on/off - hold for 5 seconds to activate lockout mode which prevents accidental activation and battery drainWaterproof - it floats! - can be submerged in 1m of water for up to 30 minutesPlastic S-Biner for clippability onto a rucksackRun time: 60 hours4x replaceable AG-3 batteries includedDiameter: 19.1mmLength: 157mmWeight: 18g