Exposure Zenith Mk4 - with Helmet and HB mounts - USB/C

The Exposure Lights Zenith Mk4 is a helmet-mounted bike light that puts out up to 2360 lumens from three LEDs, with the battery built into a 150 g aluminium body. It throws a 12 degree spot beam, charges by USB-C and is rated IP67 for water and IK09 for impact. Helmet and handlebar mounts are included.

Who it's for

Mountain bikers who ride singletrack at night and want light that follows their eyes. A helmet light points where you look: through the switchback, over the drop, down the trail past the next corner. At 150 g with no separate battery pack and no cable, the Zenith Mk4 sits on the helmet for a full night lap, and it pairs with a bar light for fast descending.

Brightness and runtime together

Runtime runs from 1 hour to 36 hours, set by the program you choose. The Zenith Mk4 has six lighting programs, each with two or three modes, and the rule is simple: double the runtime and you halve the output. Pick the program that matches the length of your ride and the light holds a constant output for the whole of it.

The light arrives set to program 4, which gives the full 2360 lumens in High and 6 hours in Low. Flash mode runs for more than 24 hours. With TAP switched on you change modes by tapping the light body or your helmet, so your hands stay on the bars, and three sensitivity settings let you tune it to your riding.

Beam shape

A diffused 12 degree spot. That is a tight beam with soft edges, made to reach down the trail and light the line you are looking at, which is the job of a helmet light.

Charging and battery

The 6,000 mAh lithium-ion battery charges through a USB-C port in 2 hours 45 minutes from empty, from a wall charger or a power bank. You can run the light while it charges. A traffic-light display on the back shows battery level the whole time the light is on, and one press of the button shows it for five seconds when the light is off.

Mounting

The helmet mount passes through a helmet vent and clamps with a nylon bolt, with two bolt lengths supplied for helmets from 22 mm to 40 mm thick. The nylon bolt is a designed break point in a crash. The mount has an action camera interface, so the light also fits action camera mounts you already own. It works with MIPS Essential, Evolve and Air Node helmets, and is not for MIPS Spherical or Integra helmets. A handlebar bracket for round bars is included as well; switch TAP off when the light is on the bars.

Weather resistance

The Zenith Mk4 is rated IP67 for water ingress and IK09 for impact. The body is CNC machined from 6063 aluminium with a gunmetal grey hard anodised finish.

Looking after it

Wipe the light down with a soft cloth and lukewarm soapy water, and keep the pressure washer away from it. Charge it fully before storing it, and top it up every 6 to 8 weeks if it sits unused over summer.