Here are the key features you'll typically find in modern helmet brake lights:

1. Wireless Operation:

   • Accelerometer/Gyroscope Sensor: The most common and advanced method. These sensors detect deceleration (when you slow down or brake) and automatically illuminate the light. This means no wiring to your bike!
   • Transmitter (Optional for some systems): Some systems might use a small transmitter wired to your bike's brake light circuit, which then wirelessly signals the helmet light to illuminate. This is less common for "automatic" brake lights but can be found.

2. Increased Visibility & Safety:

   • High Mounting Position: A helmet-mounted light is significantly higher than your motorcycle's tail light, placing it directly in the line of sight of following drivers, especially those in taller vehicles (trucks, SUVs).
   • Faster Recognition: The higher position and often brighter LEDs allow drivers to react more quickly to your braking.
   • Warning in All Scenarios: Useful even when engine braking or downshifting without using the foot/hand brake, as the accelerometer detects the deceleration.

3. LED Technology:

   • Bright & Efficient: Uses high-intensity LEDs (Light Emitting Diodes) for maximum brightness and low power consumption.
   • Various Light Patterns: Can offer steady illumination, flashing patterns, or pulsing effects for different levels of attention-grabbing. Some might have a "hazard" mode.

4. Rechargeable Battery:

   • USB Charging: Most units are powered by an internal rechargeable lithium-ion battery, typically charged via a micro-USB or USB-C port.
   • Battery Life Indicator: Often includes an indicator (e.g., LED color change) to show battery status.
   • Long Battery Life: Designed to last for many hours of riding on a single charge.

5. Easy Installation & Compatibility:

   • Universal Mounting: Designed to attach to most helmets (full-face, open-face, modular) using strong adhesive pads or clips.
   • Lightweight & Compact: Small and unobtrusive, adding minimal weight or bulk to the helmet.

6. Weather Resistance:

   • Waterproof/Weatherproof: Built to withstand rain, splashes, and various riding conditions.

7. Automatic On/Off (Smart Features):

   • Some advanced units can detect when the helmet is put on or taken off, automatically turning the light on or off to conserve battery.
   • Auto-sleep function when stationary for a period.

8. App Connectivity (for premium models):

   • Some higher-end models might connect to a smartphone app via Bluetooth, allowing you to:
     • Customize light patterns and brightness.
     • Check battery status.
     • Update firmware.
     • View ride data.