MENU LOG IN CART {{currentCart.getItemCount()}}
Theta-K - StVZO approved headlight with 35 Lux and built-in Ambient Sensor, wide beam illumination & power indicator. Tool-free mounting.

Theta-K - StVZO approved headlight with 35 Lux and built-in Ambient Sensor, wide beam illumination & power indicator. Tool-free mounting.

{{ title.name_translations | translateModel }}
The maximum quantity per submit is 99999
This quantity is invalid, please enter a valid quantity.

Not enough stock.
Your item was not added to your cart.

Not enough stock.
Please adjust your quantity.

Limit {{ product.max_order_quantity }} per order.

Only {{ quantityOfStock }} item(s) left.

Please message the shop owner for order details.


The GUEE Theta-K is a great headlight for anyone planning to ride in the dark. Night riding cyclists need both focused light so they can clearly see and avoid obstacles in their way as well as a wide field of illumination so that they too, can be seen. The GUEE Theta-K provides a solution for bicycle riders which achieves both optimal brightness and light distribution with a super-bright CREE LED - and it has been approved by the German StVZO. StVZO is a German acronym (Straßenverkehrs-Zulassungs-Ordnung) and roughly translates to road traffic licensing authority. Lights are required to have a minimum brightness, a beam pattern with a horizontal cut-off, and the brightness must be below a certain value for a certain height to protect oncoming traffic from being dazzled. The beam of our GUEE Theta-K is focused from the front wheel out to 10 meters in front of the bicycle, as well as being distributed in a wider arc in front of the wheel, illuminating the rider's path. 

The built-in smart auto sensor (SAS) automatically controls the brightness depending on the light conditions of your surroundings. The built-in rechargeable battery is easy to charge via USB and has a 4-level battery indicator so you know how much power you've got left. The tool-free, quick-release buckle of the GUEE Theta-K allows you to take off the front bike light whenever you have to leave your ride. For rainy weather, the GUEE Theta-K is IPX5 approved, which means you can ride even with water jets coming from any direction.


  • The beam design meets the StVZO (German road traffic licensing authority) standard.
  • Special beams designed to avoid dazzling oncoming traffic and increase visibility & safety.
  • The beam includes ① focused light from the front wheel out to 30 meters, ② floodlight distributed in a wide arc in front of the wheel, illuminating surroundings and road conditions.
  • Built-in auto light sensor (Smart Ambient Sensor) for auto brightness control.
  • Power indicator with 4 levels allows for easy check of power status.
  • Built-in rechargeable battery, easy to charge via USB.


  • Modes: Automatic & Manual (High/ low)
  • Light: CREE hi-power LED
  • Battery: 3.7V Li-Polymer rechargeable battery (1000mAh)
  • Charge: Micro USB power supply 5V
  • Charge time(approx): 3 hours
  • Run time(approx): 2.5hrs (High) / 5hrs (Low)
  • Mount size: ø 22.2 /31.8mm

Package includes

  • GUEE Theta-K LED bike headlight (StVZO approved) *1
  • Bracket *1
  • USB charge cable *1
  • User manual *1 


Related Products