Red: 2th in the visibility, efficiency is same as white but the best for warning.Green: 3th in the visibility and efficiency.Blue: 4th in visibility and also efficiency. We are not suggesting this color for warning or navigation but special usage.We recommend mounting one light on top of the aircraft and one on the bottom for 360 degree coverage. This greatly improve visibility for pilot from ground up and aviation looking down. Our new Dual Strobe lights with 3 modes, fixed, flash and spot. Fully independent no wiring needed all you need to provide strobes and spot lighting that can assist in maintaining orientation, spotting down or lost drones as well as meets the FAA 107 rule for strobes during night or twilight flights. These can be easily mounted on all Drones and RC Fixed Wing Planes and should be mounted one on top and one on bottom for 360 degree coverage.They are independent of the aircraft electrical system and are powered by there own internal lipo batteries so they do not steal from flight time, not do the reduce flight time due to weight or drag. This pack includes what most customers were buying individually for there aircraft. Thus we created this listing as a one stop shop to get a complete set. Set includes the following: 2- "Dual" Cree Strobe Lights, USB Charge Cable for lights and 3M mounting tape.Because of human eye's limitations, Every color has different visibility and energy transfer rate.Less Thanb