If you've ever wanted to try being invisible, cycling on a busy road at night is a good start. Adding front and rear lights is obviously a good move, but for side-on visibility, things get a little more tricky. Italian cycling company Elite is trying to solve that with something surprisingly simple: a light-up water bottle.
Campers have long used the trick of dropping a glowstick in a water bottle to get a more diffuse, spread-out light. The Candea water bottle does the same thing, by putting LED lights in the bottom of a translucent white water bottle. Stick that in the bottle cage on your bike, and you have good side-on visibility, without having to spray-paint anything, or even attach a new mount to your your bike.
Apart from the lights, the Candea is just a 650ml water bottle. I've used the non-light version of the same bottle for years, and it's well-built, with one of the best drinking tops around. Add those lights, and it's well worth the $US30 it will cost you to buy it right now.