TL:TR Highly functional light with clever features, some teething problems
If you like to ride through the unlit woods at night, Double-O isn't for you, but that would.
It is a commuter light with a rather clever design.
- It is huge. With the LED arranged in a circle you get a big patch of light, a much bigger surface than the bike lights you commonly find in the market. That alone improves visibility quite a bit.
- Two of the 3 light modes are what you would expect: blinking and steady. The third one I haven't seen elsewhere: the odd and even numbered LED blink alternate. This is quite clever. Someone looking at it (that's: the other traffic participants) sees something moving, creating similar attention as blinking, but for the rider it is a steady light since the same number of LED is on at any given time. That's especially useful for the front light lighting the path (to some extend) in front of you.
- The case is sturdy and the threaded cover that you use to screw it open and close (to change batteries) reliably keeps moisture out (trust me, my environment has plenty of that
- The rubber band mechanism and the rubberised back making fixing the light at a handlebar or a seat stem very fast and reliable. My package even included a set of spare rubbers
- Locking the lights with your bike lock works as advertised (but someone could steal the batteries if they get what it hanging there)
- The low power LED lights make the batteries last quite long
The BadThe original specifications proposed to use USB chargable fixed batteries and a magnetic fix for the light. The rechargable option was abandoned in favour of longer lasting standard batteries (and rechargeable battery in the Kickstarter delivery). While I generally understand the design decision for a general market offering, I would have found USB charging suiting my personal style (I'm used to have a zoo to be charged after my rides: The Garmin, the Bluetooth entertainment, the phone and the helmet).
The rubber band to fix the light at the bike works and it more efficient to produce, but the magnet solution has a way bigger cool factor. Also: When there's no pipe (read saddle stem) available or you want to fix it at your pannier rack, the rubber isn't the best fit. Eventually Double-O might release the fixtures design files, so I can print one for my purpose.
The UglyThe battery holding mechanism (see the picture above) is flimsy. For a hipster ride that might be sufficient, but in a little rugged environment where I ride (kerbstone jumps, potholes, very uneven surface, the occasional trail) the vibrations make the batteries move, in my case even to the extend of bending the electrical contract latches. The batteries loose contact and the light goes off (or won't switch on).
I haven't found a solution, but I'm contemplating using a rubber ring around battery and latch or hold the pieces in place using a little dense sponge rubber.