Each HueRay grip has two LED bulbs contained within an impact- and weather-resistant polycarbonate housing, for an output of 90 lumens per grip. Those housings sit within a slot at the end of each grip, shining through the silicone when activated.
A 200-mAh lithium-polymer battery in each unit provides a claimed six hours of run time in Flash mode, or three hours in Steady. When the batteries need to be recharged (or even just when the bike is being left unattended), the light housings can easily be pulled out of their slots and carried with the rider. To make things simpler, the two housings can then be stuck together like Lego, and charged simultaneously via an included double-ended USB cable.
If you're interested, HueRay grips are currently the subject of a Kickstarter campaign. A pledge of US$50 will currently get a set in your choice of six colors, when and if they reach production. The planned retail price is $99.