Description The Knog Cobber Reflex Rear Light is a dynamic rear bike light that responds to the bike leaning, braking or going over bumps by changing the output & display of the LEDs. Neat tech that communicates to the cyclists behind you, and catches the eye of motorists! 250 lumen USB-C rechargeable IP67 water resistant Motion activated light 4 light modes from HYPE flash to constant Supplied with strap for mounting to seat posts 2 year warranty Recommended uses: Road, Urban commutes This rear light has the newest & best tech from Knog so far – Adaptive Reflex Technology. The cobber light output is a series of small dots of LEDs on a curved panel. Meaning it’s been awesome for side-visibility and a big powerful wall of light that’s easy to see from a distance. But adding the new Reflex tech to the light adds more functionality. Using the dots of light to indicate changes – so when you lean right the light pattern strobes in the corresponding direction. And when you’re braking the light responds to your deceleration by increasing the output to warn those behind you. Your light’s communicating for you – it’s telling people behind you valuable information, making you safer! Knog Cobber Reflex Rear Light Specs 250 lumens USB-C rechargeable (cable not included) Supplied with Quick Release silicone straps for mounting to different sized seatposts 5 light modes with outputs from 20 to 250 lumens 2.5-70 hours run time depending on mode selected 4 hours charge time Dimensions: 64 mm H x 34mm W x 25mm D Weight: 39 g