The Varia™ RTL 500 default light mode is flash mode. The four middle LEDs flash at all times. When a vehicle is detected, additional LEDs progressively turn on and the flashing increases frequency as the vehicle gets closer to your bike. You can switch the device to solid mode by pressing the device key.

The Varia RTL 501 has the solid mode only. The two middle LEDs are solid at all times. When a vehicle is detected, additional LEDs progressively turn on as the vehicle gets closer to your bike.