Five thousand lumens of remotecontrolled power for $300 sounds a good deal, but our trail testing found serious flaws with the Zeta. The six-LED head unit uses an O-ring mount for universal bar compatibility, but its weight makes it shake downwards on rough descents unless you add textured grip tape. Max power looks barely half that claimed, and can only be accessed by keeping the remote button pressed down (compromising grip), with a warning to not exceed 30 seconds. The ‘high power’ mode is weaker than that of most 1,500-lumen lights. We also had repeated ignition/ control issues with the main switch and remote, making a couple of rides non-starters. That all makes the Zeta hard to recommend despite decent battery life and what sounds like promising performance on paper. Weight 425g Run time (max power) 2hrs 10mins Price $313