LED light signal, white and blue, LS series, stainless steel (painted aluminum) with white and blue LEDs Operation only with power supply item no. SV 539 LED or SV 539-948 LED. When connected to L and N or F1 and the power supply, the white LEDs are energized, when connected to L' and N or F2 and the blue LEDs are energized (L + L' and N or F1 + F2 and is possible). Can be labeled with foil