The Sirius Mk9 + Trace ReAKT Pack is a premium package with high power in a compact front light that is as at home in either a road race or lighting the urban commute. Combined with an intelligent and extremely lightweight rear light featuring Ambient Kinetic Technology (ReAKT) enables the light to automatically flare under braking and when entering areas of higher ambient light to create a contrast in brightness.850 lumen front light with a 75 lumen rear light that jumps to 120 lumens using ReAKT Smart Port+ enables the charge port to accept auxiliary accessories such as rear lights, remote switches, Support Cells and to use your light as a power bank to charge USB devicesIntelligent Thermal Management prevents overheating and maximizing battery lifeOptimised Mode Selector allows rider to fine tune power and run times for the rideEasy to read Fuel Gauge for monitoring run timeReAKT rear lighting that flares up automatically under braking and adapts to the surrounding ambient light conditions to maintain maximum contrast and visibility