Exposure Boost-R 3 with ReAkt

The Exposure Boost-R 3 with ReAKT is a compact, CNC-machined aluminium rear light for commuting and road riding that thinks for itself: it brightens as a brake light when you slow, adapts to the light around you, and dims for the rider sitting on your wheel. It is 45 g, 60 mm long, sealed to IP67 and charges by USB-C.

What it fits

The Boost-R 3 comes with a seatpost mount and silicone band. The bracket is angled so the light points straight back once it is fitted, and shims for differently shaped seatposts, plus saddle rail, rack and other brackets, let it go where your bike has room. It is built for the daily commute through Brisbane traffic, early bunch rides and long days on the road bike, day or night.

How it attaches

The silicone band stretches around the post and locks into a groove on the bracket, with no tools needed. The light slides into the bracket and twists a quarter turn to lock in, and a quarter turn back releases it, so it comes off in a second when you lock the bike up outside the office.

Brightness and runtime

Three programs trade brightness for runtime, and each has a constant and a pulse mode. Program 1 gives 75 lumens constant for 6 hours, or 12 hours on pulse. Program 2 runs 12 hours constant or 24 hours pulse, and program 3 runs 24 hours constant or up to 70 hours pulse. The run times are etched on the body, so you do not need to remember them.

DayBright is Exposure's pulse pattern for daylight riding, visible from over a kilometre away, for when the sun is up and the traffic is heavy. An 8 degree collimated spot lens throws the light a long way back, and the 270 degree Commute Lens spreads it to the sides so cars pulling out of a side street see you too.

ReAKT and Peloton

ReAKT does two jobs. It senses deceleration and flares the light as a brake light, in constant and pulse modes. It also reads the ambient light, lifting output under street lights or in bright sun and easing off in darker places to save the battery. Peloton dims the light when it detects the front light of a rider behind you, so the bunch is not riding into a glare, then returns to your setting once they drop off. Each is switched on through the program selector and stays on until you turn it off.

Charging and battery

The 1,600 mAh lithium-ion battery charges by USB-C in about 1.5 hours, including from a power bank. The port hides under a tab on the silicone band; tuck the band back into its groove after charging to keep water out. A single press while the light is off shows the charge level for five seconds: green for 50 to 100%, amber for 25 to 50%, red for 5 to 25%, flashing red below 5%.

Weight and material

The body is CNC-machined 6063 aluminium, anodised, 60 mm long with a 28 mm head, and it weighs 45 g. It is rated IP67 against water and dust and tested to IK09 for impact. Intelligent Thermal Management trims power to the LED if it runs hot and restores it once it cools.

Looking after it

Wipe the light down with lukewarm soapy water, never a pressure washer, and rinse it with fresh water after a coastal ride in salt spray. If it is going to sit for a while, store it charged and top it up every six to eight weeks.