The Kryptonite XBR taillight uses a built-in accelerometer to provide a brake light which increases output 3x over the steady mode. 7 Modes including a daytime brake mode for 10-36 hours of runtime before needing a recharge via USB.

• Acceleration sensor: when speed is reduced by more than 1.6 m/s, (5.76 km/hr or 3.58 mph) an additional LED is switched on
• Low battery indicator displays red if battery capacity under 25%

Specs

• Recharge Type:USB
• Weight:20 g

Taillight mode / run time

• High Steady (w/Brake function): 10 hrs
• Daytime Brakelight Mode
• High Flash: 20 hrs
• Low Steady (w/Brake function) : 20 hrs
• Daytime Pulse: 22 hrs
• Nighttime Pulse: 18 hrs
• Economic Flash: 36 hrs