The PWR Lighthead 1100L is part of Knog's PWR Range. Compatible with the small, medium and large PWR Banks you can build the bike light that you want. The PWR Lighthead 1100L outputs an elliptical style beam with a horizontal and vertical spread for broader and brighter road coverage, combined with an additional ring of "be seen" LEDs. You can also program the light to suit your needs with Knog's Modemaker app “ control brightness, adjust runtimes and add new light modes. BROAD AND BRIGHT COVERAGE - The PWR Lighthead 1100L outputs an elliptical style beam for broader and brighter road coverage. This modular 1100 lumen lighthead can be swapped between small, medium and large PWR Bank batteries for longer runtimes. PROGRAM YOUR LIGHT - When Knog designs each light, we put optics at the heart of that equation. Whether it's new LED formations, or beam patterns, we are committed to making each lumen work harder once you're on the road. You can program the light to suit your needs with Modemaker “ control brightness, adjust runtimes and add new light modes. SPECIFICATION Dimensions - H: 45mm x W: 35mm x L:35mm. Weight - 54 grams. Lumens - 1100. Runtimes if lighthead is paired with PWR Bank Small. INSTRUCTIONS Operation: PWR Lightheads have no buttons! Instead we use rotation to switch the light on & between modes. To turn light On / Off: Rotate the lighthead until it stops and hold in place for 1 second or until the light turns on / off. To change the modes: Once the light is on, you can simply change the mode by rotating the light head until it stops. It will spring back into position.